snyk/snyk-demo-app

A demo application for Snyk.
Vulnerabilities 27 via 104 paths
Dependencies 273
Source GitHub
Commit 2f31650f

Find, fix and prevent vulnerabilities in your code.

Severity
  • 9
  • 14
  • 4
Status
  • 27
  • 0
  • 0
high severity

Arbitrary Code Injection

  • Vulnerable module: pouchdb
  • Introduced through: falcor-router-demo@1.0.3

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0

Overview

pouchDB is an open-source JavaScript database inspired by Apache CouchDB that is designed to run well within the browser.

Vulnerable versions of the package had the evalView function in pouchdb-core to execute the view function without a sandbox. The fix was introduced in version 6.0.5, executing the view function in a sandbox and enforcing strict mode when running in Node.js.

The vulnerability was reported by micaksica.

Remediation

Upgrade pouchDB to version 6.0.5 or later.

References

high severity

Denial of Service (Memory Exhaustion)

  • Vulnerable module: qs
  • Introduced through: falcor-router-demo@1.0.3

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0 request@2.28.0 qs@0.6.6
    Remediation: Upgrade to falcor-router-demo@1.0.5.

Overview

qs is a querystring parser that supports nesting and arrays, with a depth limit.

Affected versions of this package are vulnerable to Denial of Service (Memory Exhaustion). During parsing, the qs module may create a sparse area (an array where no elements are filled), and grow that array to the necessary size based on the indices used on it. An attacker can specify a high index value in a query string, thus making the server allocate a respectively big array. Truly large values can cause the server to run out of memory and cause it to crash - thus enabling a Denial-of-Service attack.

Remediation

Upgrade qs to version 1.0.0 or higher.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

  • High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

  • Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package

References

high severity

Denial of Service through invalid If-Modified-Since/Last-Modified headers

  • Vulnerable module: hapi
  • Introduced through: hapi@10.5.0

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0
    Remediation: Upgrade to hapi@11.1.3.

Overview

Sending a purposefully crafted invalid date in the If-Modified-Since or Last-Modified header will cause the Hapi server to err but keep the socket open (the socket will time out after 2 minutes by default). This allows an attacker to quickly exhaust the sockets on the server, making it unavailable (a Denial of Service attack).

The vulnerability is caused by the combination of two bugs. First, the underlying V8 engine throws an exception when processing the specially crafted date, instead of stating the date is invalid as it should. Second, the Hapi server does not handle the exception well, leading to the socket remaining open.

Upgrading Hapi will address the second issue and thus fix the vulnerability.

References

high severity

Prototype Override Protection Bypass

  • Vulnerable module: qs
  • Introduced through: azure-mgmt-storage@0.9.16, falcor-router-demo@1.0.3 and others

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d azure-mgmt-storage@0.9.16 azure-common@0.9.11 request@2.45.0 qs@1.2.2
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0 request@2.28.0 qs@0.6.6
    Remediation: Upgrade to falcor-router-demo@1.0.5.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 qs@4.0.0
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 qs@5.2.1
    Remediation: Upgrade to hapi@11.0.4.

Overview

qs is a querystring parser that supports nesting and arrays, with a depth limit.

By default qs protects against attacks that attempt to overwrite an object's existing prototype properties, such as toString(), hasOwnProperty(),etc.

From qs documentation:

By default parameters that would overwrite properties on the object prototype are ignored, if you wish to keep the data from those fields either use plainObjects as mentioned above, or set allowPrototypes to true which will allow user input to overwrite those properties. WARNING It is generally a bad idea to enable this option as it can cause problems when attempting to use the properties that have been overwritten. Always be careful with this option.

Overwriting these properties can impact application logic, potentially allowing attackers to work around security controls, modify data, make the application unstable and more.

In versions of the package affected by this vulnerability, it is possible to circumvent this protection and overwrite prototype properties and functions by prefixing the name of the parameter with [ or ]. e.g. qs.parse("]=toString") will return {toString = true}, as a result, calling toString() on the object will throw an exception.

Example:

qs.parse('toString=foo', { allowPrototypes: false })
// {}

qs.parse("]=toString", { allowPrototypes: false })
// {toString = true} <== prototype overwritten

For more information, you can check out our blog.

Disclosure Timeline

  • February 13th, 2017 - Reported the issue to package owner.
  • February 13th, 2017 - Issue acknowledged by package owner.
  • February 16th, 2017 - Partial fix released in versions 6.0.3, 6.1.1, 6.2.2, 6.3.1.
  • March 6th, 2017 - Final fix released in versions 6.4.0,6.3.2, 6.2.3, 6.1.2 and 6.0.4

Remediation

Upgrade qs to version 6.4.0 or higher. Note: The fix was backported to the following versions 6.3.2, 6.2.3, 6.1.2, 6.0.4.

References

high severity

Prototype Pollution

  • Vulnerable module: handlebars
  • Introduced through: snyk-demo-child@0.0.1

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d snyk-demo-child@0.0.1 handlebars@3.0.7

Overview

handlebars is a extension to the Mustache templating language.

Affected versions of this package are vulnerable to Prototype Pollution. Templates may alter an Objects' prototype, thus allowing an attacker to execute arbitrary code on the server.

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as _proto_, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named _proto_ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to _proto_.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade handlebars to version 4.0.13 or higher.

References

high severity

Prototype Pollution

  • Vulnerable module: handlebars
  • Introduced through: snyk-demo-child@0.0.1

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d snyk-demo-child@0.0.1 handlebars@3.0.7

Overview

handlebars is a extension to the Mustache templating language.

Affected versions of this package are vulnerable to Prototype Pollution. A Prototype Pollution allowing Remote Code Execution can be exploited using the constructor, via the 'lookup' helper. This vulnerability is due to an incomplete fix for: SNYK-JS-HANDLEBARS-173692

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as _proto_, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named _proto_ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to _proto_.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade handlebars to version 4.1.2, 4.0.14 or higher.

References

high severity

Regular Expression Denial of Service (DoS)

  • Vulnerable module: validator
  • Introduced through: azure-mgmt-storage@0.9.16

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d azure-mgmt-storage@0.9.16 azure-common@0.9.11 validator@3.1.0

Overview

validator is a library of string validators and sanitizers.

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) attacks. It used a regular expression in order to validate URLs.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Update to version 3.22.1 or greater.

References

high severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: content
  • Introduced through: hapi@10.5.0

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 content@1.0.2
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 pez@1.0.0 content@1.0.2
    Remediation: Upgrade to hapi@11.0.4.

Overview

content is a HTTP Content-* headers parsing

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) attacks. An attacker may pass a specially crafted Content-Type or Content-Disposition header, causing the server to hang. This can cause an impact of about 10 seconds matching time for data 180 characters long.

Disclosure Timeline

  • Feb 5th, 2018 - Initial Disclosure to package owner
  • Feb 5th, 2018 - Initial Response from package owner
  • Feb 28th, 2018 - Fix issued
  • Mar 5th, 2018 - Vulnerability published

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade content to versions 3.0.7, 4.0.4 or higher

References

high severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: tough-cookie
  • Introduced through: falcor-router-demo@1.0.3

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0 request@2.28.0 tough-cookie@0.9.15
    Remediation: Upgrade to falcor-router-demo@1.0.5.

Overview

tough-cookie is a RFC6265 Cookies and CookieJar module for Node.js.

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS). An attacker can provide a cookie, which nearly matches the pattern being matched. This will cause the regular expression matching to take a long time, all the while occupying the event loop and preventing it from processing other requests and making the server unavailable (a Denial of Service attack).

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade tough-cookie to version 2.3.0 or higher.

References

medium severity

Arbitrary JavaScript Code Injection

  • Vulnerable module: bassmaster
  • Introduced through: bassmaster@1.5.1

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d bassmaster@1.5.1
    Remediation: Upgrade to bassmaster@1.5.2.

Overview

Old versions of bassmaster, a Hapi server plugin used to process batches of requests, use the eval method as part of its processing and validation of user input.

An attacker can therefore provide arbitrary javascript in this input, which will be executed by this eval function without limitation.

This is a very severe remote JavaScript code execution, and depending on the node process permissions can turn into Arbitrary Remote Code Execution on the operating system level as well.

Remediation

Update to bassmaster version 1.5.2 or greater.

References

medium severity

Buffer Overflow

  • Vulnerable module: validator
  • Introduced through: azure-mgmt-storage@0.9.16

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d azure-mgmt-storage@0.9.16 azure-common@0.9.11 validator@3.1.0

Overview

validator is a library of string validators and sanitizers.

Affected versions of this package are vulnerable to Buffer Overflow. It used a regular expression (/^(?:[A-Z0-9+\/]{4})*(?:[A-Z0-9+\/]{2}==|[A-Z0-9+\/]{3}=|[A-Z0-9+\/]{4})$/i) in order to validate Base64 strings.

Remediation

Upgrade validator to version 5.0.0 or higher.

References

medium severity

Cross-site Scripting (XSS)

  • Vulnerable module: handlebars
  • Introduced through: snyk-demo-child@0.0.1

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d snyk-demo-child@0.0.1 handlebars@3.0.7
    Remediation: Open PR to patch handlebars@3.0.7.

Overview

handlebars provides the power necessary to let you build semantic templates.

When using attributes without quotes in a handlebars template, an attacker can manipulate the input to introduce additional attributes, potentially executing code. This may lead to a Cross-site Scripting (XSS) vulnerability, assuming an attacker can influence the value entered into the template. If the handlebars template is used to render user-generated content, this vulnerability may escalate to a persistent XSS vulnerability.

Details

Cross-Site Scripting (XSS) attacks occur when an attacker tricks a user’s browser to execute malicious JavaScript code in the context of a victim’s domain. Such scripts can steal the user’s session cookies for the domain, scrape or modify its content, and perform or modify actions on the user’s behalf, actions typically blocked by the browser’s Same Origin Policy.

These attacks are possible by escaping the context of the web application and injecting malicious scripts in an otherwise trusted website. These scripts can introduce additional attributes (say, a "new" option in a dropdown list or a new link to a malicious site) and can potentially execute code on the clients side, unbeknown to the victim. This occurs when characters like < > " ' are not escaped properly.

There are a few types of XSS:

  • Persistent XSS is an attack in which the malicious code persists into the web app’s database.
  • Reflected XSS is an which the website echoes back a portion of the request. The attacker needs to trick the user into clicking a malicious link (for instance through a phishing email or malicious JS on another page), which triggers the XSS attack.
  • DOM-based XSS is an that occurs purely in the browser when client-side JavaScript echoes back a portion of the URL onto the page. DOM-Based XSS is notoriously hard to detect, as the server never gets a chance to see the attack taking place.

Example:

Assume handlebars was used to display user comments and avatar, using the following template: <img src={{avatarUrl}}><pre>{{comment}}</pre>

If an attacker spoofed their avatar URL and provided the following value: http://evil.org/avatar.png onload=alert(document.cookie)

The resulting HTML would be the following, triggering the script once the image loads: <img src=http://evil.org/avatar.png onload=alert(document.cookie)><pre>Gotcha!</pre>

References

medium severity

Cross-site Scripting (XSS)

  • Vulnerable module: validator
  • Introduced through: azure-mgmt-storage@0.9.16

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d azure-mgmt-storage@0.9.16 azure-common@0.9.11 validator@3.1.0

Overview

validator is a library of string validators and sanitizers.

Affected versions of this package are vulnerable to Cross-site Scripting (XSS) in IE9 due to unescaped backticks.

Details

A cross-site scripting attack occurs when the attacker tricks a legitimate web-based application or site to accept a request as originating from a trusted source.

This is done by escaping the context of the web application; the web application then delivers that data to its users along with other trusted dynamic content, without validating it. The browser unknowingly executes malicious script on the client side (through client-side languages; usually JavaScript or HTML) in order to perform actions that are otherwise typically blocked by the browser’s Same Origin Policy.

ֿInjecting malicious code is the most prevalent manner by which XSS is exploited; for this reason, escaping characters in order to prevent this manipulation is the top method for securing code against this vulnerability.

Escaping means that the application is coded to mark key characters, and particularly key characters included in user input, to prevent those characters from being interpreted in a dangerous context. For example, in HTML, < can be coded as &lt; and > can be coded as &gt; in order to be interpreted and displayed as themselves in text, while within the code itself, they are used for HTML tags. If malicious content is injected into an application that escapes special characters and that malicious content uses < and > as HTML tags, those characters are nonetheless not interpreted as HTML tags by the browser if they’ve been correctly escaped in the application code and in this way the attempted attack is diverted.

The most prominent use of XSS is to steal cookies (source: OWASP HttpOnly) and hijack user sessions, but XSS exploits have been used to expose sensitive information, enable access to privileged services and functionality and deliver malware.

Types of attacks

There are a few methods by which XSS can be manipulated:

Type Origin Description
Stored Server The malicious code is inserted in the application (usually as a link) by the attacker. The code is activated every time a user clicks the link.
Reflected Server The attacker delivers a malicious link externally from the vulnerable web site application to a user. When clicked, malicious code is sent to the vulnerable web site, which reflects the attack back to the user’s browser.
DOM-based Client The attacker forces the user’s browser to render a malicious page. The data in the page itself delivers the cross-site scripting data.
Mutated The attacker injects code that appears safe, but is then rewritten and modified by the browser, while parsing the markup. An example is rebalancing unclosed quotation marks or even adding quotation marks to unquoted parameters.

Affected environments

The following environments are susceptible to an XSS attack:

  • Web servers
  • Application servers
  • Web application environments

How to prevent

This section describes the top best practices designed to specifically protect your code:

  • Sanitize data input in an HTTP request before reflecting it back, ensuring all data is validated, filtered or escaped before echoing anything back to the user, such as the values of query parameters during searches.
  • Convert special characters such as ?, &, /, <, > and spaces to their respective HTML or URL encoded equivalents.
  • Give users the option to disable client-side scripts.
  • Redirect invalid requests.
  • Detect simultaneous logins, including those from two separate IP addresses, and invalidate those sessions.
  • Use and enforce a Content Security Policy (source: Wikipedia) to disable any features that might be manipulated for an XSS attack.
  • Read the documentation for any of the libraries referenced in your code to understand which elements allow for embedded HTML.

Remediation

Upgrade validator to version 3.35.0 or higher.

References

medium severity

Denial of Service (Event Loop Blocking)

  • Vulnerable module: qs
  • Introduced through: falcor-router-demo@1.0.3

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0 request@2.28.0 qs@0.6.6
    Remediation: Upgrade to falcor-router-demo@1.0.5.

Overview

qs is a querystring parser that supports nesting and arrays, with a depth limit.

Affected versions of this package are vulnerable to Denial of Service (DoS). When parsing a string representing a deeply nested object, qs will block the event loop for long periods of time. Such a delay may hold up the server's resources, keeping it from processing other requests in the meantime, thus enabling a Denial-of-Service attack.

Remediation

Update qs to version 1.0.0 or higher. In these versions, qs enforces a max object depth (along with other limits), limiting the event loop length and thus preventing such an attack.

References

medium severity

Improper input validation

  • Vulnerable module: call
  • Introduced through: hapi@10.5.0

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 call@2.0.2
    Remediation: Upgrade to hapi@11.0.4.

Overview

call is the primary HTTP router of the hapi framework.

The vulnerability arise from undefined values inside a path (last segment being an exception) making their way into components that do not care for values being undefined (eg. the database layer).

For example, the request URI /delete/company// may incorrectly match a route looking for /delete/company/{company}/. By itself, the bad match is not a vulnerability. However, depending on the remaining logic in the application, such a bad match may result in skipping a protection mechanisms. In the above example, if the route translates to a DB delete command, it might delete all the companies from the db.

Remediation

Upgrade to version 3.0.2 or higher.

References

https://github.com/hapijs/hapi/issues/3228 https://github.com/hapijs/call/commit/9570eee5358b4383715cc6a13cb95971678efd30

medium severity

Prototype Pollution

  • Vulnerable module: hoek
  • Introduced through: azure-mgmt-storage@0.9.16, falcor-router-demo@1.0.3 and others

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d azure-mgmt-storage@0.9.16 azure-common@0.9.11 request@2.45.0 hawk@1.1.1 hoek@0.9.1
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0 request@2.28.0 hawk@1.0.0 hoek@0.9.1
    Remediation: Upgrade to falcor-router-demo@1.0.5.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d azure-mgmt-storage@0.9.16 azure-common@0.9.11 request@2.45.0 hawk@1.1.1 boom@0.4.2 hoek@0.9.1
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0 request@2.28.0 hawk@1.0.0 boom@0.4.2 hoek@0.9.1
    Remediation: Upgrade to falcor-router-demo@1.0.5.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d azure-mgmt-storage@0.9.16 azure-common@0.9.11 request@2.45.0 hawk@1.1.1 sntp@0.2.4 hoek@0.9.1
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0 request@2.28.0 hawk@1.0.0 sntp@0.2.4 hoek@0.9.1
    Remediation: Upgrade to falcor-router-demo@1.0.5.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d azure-mgmt-storage@0.9.16 azure-common@0.9.11 request@2.45.0 hawk@1.1.1 cryptiles@0.2.2 boom@0.4.2 hoek@0.9.1
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0 request@2.28.0 hawk@1.0.0 cryptiles@0.2.2 boom@0.4.2 hoek@0.9.1
    Remediation: Upgrade to falcor-router-demo@1.0.5.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d inert@3.2.1 hoek@2.16.3
    Remediation: Upgrade to inert@4.0.0.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 hoek@2.16.3
    Remediation: Upgrade to hapi@13.4.0.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d bassmaster@1.5.1 hoek@2.16.3
    Remediation: Upgrade to bassmaster@2.0.0.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 hoek@2.16.3
    Remediation: Upgrade to hapi@12.0.0.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 statehood@2.1.1 hoek@2.16.3
    Remediation: Upgrade to hapi@13.0.0.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 shot@1.7.0 hoek@2.16.3
    Remediation: Upgrade to hapi@12.0.1.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 mimos@2.0.2 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 kilt@1.1.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 iron@2.1.3 hoek@2.16.3
    Remediation: Upgrade to hapi@13.0.0.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 heavy@3.0.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 catbox-memory@1.1.2 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 catbox@6.0.0 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 call@2.0.2 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d inert@3.2.1 ammo@1.0.1 hoek@2.16.3
    Remediation: Upgrade to inert@4.0.0.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 ammo@1.0.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 accept@1.1.0 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d inert@3.2.1 joi@6.10.1 hoek@2.16.3
    Remediation: Upgrade to inert@4.0.0.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 joi@6.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@13.1.0.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-hapi@netflix/falcor-hapi joi@6.10.1 hoek@2.16.3
    Remediation: Open PR to patch hoek@2.16.3.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-hapi@netflix/falcor-hapi boom@2.10.1 hoek@2.16.3
    Remediation: Open PR to patch hoek@2.16.3.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d inert@3.2.1 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to inert@4.0.0.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d bassmaster@1.5.1 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to bassmaster@2.0.0.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 topo@1.1.0 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-hapi@netflix/falcor-hapi joi@6.10.1 topo@1.1.0 hoek@2.16.3
    Remediation: Open PR to patch hoek@2.16.3.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 accept@1.1.0 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 ammo@1.0.1 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 joi@6.10.1 topo@1.1.0 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d inert@3.2.1 joi@6.10.1 topo@1.1.0 hoek@2.16.3
    Remediation: Upgrade to inert@4.0.0.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 wreck@6.3.0 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 catbox@6.0.0 joi@6.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 heavy@3.0.1 joi@6.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 statehood@2.1.1 joi@6.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@13.0.0.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 pez@1.0.0 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 content@1.0.2 hoek@2.16.3
    Remediation: Open PR to patch hoek@2.16.3.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d inert@3.2.1 ammo@1.0.1 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to inert@4.0.0.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 statehood@2.1.1 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 iron@2.1.3 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 call@2.0.2 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 heavy@3.0.1 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 catbox@6.0.0 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 statehood@2.1.1 iron@2.1.3 hoek@2.16.3
    Remediation: Upgrade to hapi@13.0.0.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 cryptiles@2.0.5 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 statehood@2.1.1 cryptiles@2.0.5 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 heavy@3.0.1 joi@6.10.1 topo@1.1.0 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 catbox@6.0.0 joi@6.10.1 topo@1.1.0 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 statehood@2.1.1 iron@2.1.3 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 statehood@2.1.1 joi@6.10.1 topo@1.1.0 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 pez@1.0.0 content@1.0.2 hoek@2.16.3
    Remediation: Open PR to patch hoek@2.16.3.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 content@1.0.2 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 iron@2.1.3 cryptiles@2.0.5 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 wreck@6.3.0 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 pez@1.0.0 nigel@1.0.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 pez@1.0.0 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 pez@1.0.0 b64@2.0.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 pez@1.0.0 nigel@1.0.1 vise@1.0.0 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 pez@1.0.0 content@1.0.2 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 statehood@2.1.1 iron@2.1.3 cryptiles@2.0.5 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to hapi@11.0.4.

Overview

hoek is a Utility methods for the hapi ecosystem.

Affected versions of this package are vulnerable to Prototype Pollution. The utilities function allow modification of the Object prototype. If an attacker can control part of the structure passed to this function, they could add or modify an existing property.

PoC by Olivier Arteau (HoLyVieR)

var Hoek = require('hoek');
var malicious_payload = '{"__proto__":{"oops":"It works !"}}';

var a = {};
console.log("Before : " + a.oops);
Hoek.merge({}, JSON.parse(malicious_payload));
console.log("After : " + a.oops);

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as _proto_, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named _proto_ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to _proto_.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade hoek to version 4.2.1, 5.0.3 or higher.

References

medium severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: content
  • Introduced through: hapi@10.5.0

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 content@1.0.2
    Remediation: Upgrade to hapi@11.0.4.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0 subtext@2.0.2 pez@1.0.0 content@1.0.2
    Remediation: Upgrade to hapi@11.0.4.

Overview

content is HTTP Content-* headers parsing.

Affected versions of this package are vulnerable to Regular expression Denial of Service (ReDoS) attacks. An attacker may pass a specially crafted Content-Type or Content-Disposition header, causing the server to hang.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade content to version 3.0.6 or higher.

References

medium severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: semver
  • Introduced through: falcor-router-demo@1.0.3

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0 levelup@0.18.6 semver@2.3.2
    Remediation: Upgrade to falcor-router-demo@1.0.5.

Overview

npm is a package manager for javascript.

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS). The semver module uses regular expressions when parsing a version string. For a carefully crafted input, the time it takes to process these regular expressions is not linear to the length of the input. Since the semver module did not enforce a limit on the version string length, an attacker could provide a long string that would take up a large amount of resources, potentially taking a server down. This issue therefore enables a potential Denial of Service attack. This is a slightly differnt variant of a typical Regular Expression Denial of Service (ReDoS) vulnerability.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Update to a version 4.3.2 or greater. From the issue description [2]: "Package version can no longer be more than 256 characters long. This prevents a situation in which parsing the version number can use exponentially more time and memory to parse, leading to a potential denial of service."

References

medium severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: tough-cookie
  • Introduced through: falcor-router-demo@1.0.3

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0 request@2.28.0 tough-cookie@0.9.15
    Remediation: Upgrade to falcor-router-demo@1.0.5.

Overview

tough-cookie is RFC6265 Cookies and Cookie Jar for node.js.

Affected versions of this package are vulnerable to Regular expression Denial of Service (ReDoS) attacks. An attacker may pass a specially crafted cookie, causing the server to hang.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade to version 2.3.3 or newer.

References

medium severity

Remote Memory Exposure

  • Vulnerable module: request
  • Introduced through: azure-mgmt-storage@0.9.16 and falcor-router-demo@1.0.3

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d azure-mgmt-storage@0.9.16 azure-common@0.9.11 request@2.45.0
    Remediation: Open PR to patch request@2.45.0.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0 request@2.28.0
    Remediation: Upgrade to falcor-router-demo@1.0.5.

Overview

request is a simplified http request client.

Affected versions of this package are vulnerable to Remote Memory Exposure. A potential remote memory exposure vulnerability exists in request. If a request uses a multipart attachment and the body type option is number with value X, then X bytes of uninitialized memory will be sent in the body of the request.

Note that while the impact of this vulnerability is high (memory exposure), exploiting it is likely difficult, as the attacker needs to somehow control the body type of the request. One potential exploit scenario is when a request is composed based on JSON input, including the body type, allowing a malicious JSON to trigger the memory leak.

Details

Constructing a Buffer class with integer N creates a Buffer of length N with non zero-ed out memory. Example:

var x = new Buffer(100); // uninitialized Buffer of length 100
// vs
var x = new Buffer('100'); // initialized Buffer with value of '100'

Initializing a multipart body in such manner will cause uninitialized memory to be sent in the body of the request.

Proof of concept

var http = require('http')
var request = require('request')

http.createServer(function (req, res) {
  var data = ''
  req.setEncoding('utf8')
  req.on('data', function (chunk) {
    console.log('data')
    data += chunk
  })
  req.on('end', function () {
    // this will print uninitialized memory from the client
    console.log('Client sent:\n', data)
  })
  res.end()
}).listen(8000)

request({
  method: 'POST',
  uri: 'http://localhost:8000',
  multipart: [{ body: 1000 }]
},
function (err, res, body) {
  if (err) return console.error('upload failed:', err)
  console.log('sent')
})

Remediation

Upgrade request to version 2.68.0 or higher.

References

medium severity

Timing Attack

  • Vulnerable module: http-signature
  • Introduced through: azure-mgmt-storage@0.9.16 and falcor-router-demo@1.0.3

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d azure-mgmt-storage@0.9.16 azure-common@0.9.11 request@2.45.0 http-signature@0.10.1
    Remediation: Open PR to patch http-signature@0.10.1.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0 request@2.28.0 http-signature@0.10.1
    Remediation: Upgrade to falcor-router-demo@1.0.5.

Overview

http-signature is a reference implementation of Joyent's HTTP Signature scheme.

Affected versions of the package are vulnerable to Timing Attacks due to time-variable comparison of signatures.

The library implemented a character to character comparison, similar to the built-in string comparison mechanism, ===, and not a time constant string comparison. As a result, the comparison will fail faster when the first characters in the signature are incorrect. An attacker can use this difference to perform a timing attack, essentially allowing them to guess the signature one character at a time.

You can read more about timing attacks in Node.js on the Snyk blog.

Remediation

Upgrade http-signature to version 1.0.0 or higher.

References

medium severity

Uninitialized Memory Exposure

  • Vulnerable module: bl
  • Introduced through: falcor-router-demo@1.0.3

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0 levelup@0.18.6 bl@0.8.2

Overview

bl is a storage object for collections of Node Buffers.

A possible memory disclosure vulnerability exists when a value of type number is provided to the append() method and results in concatenation of uninitialized memory to the buffer collection.

This is a result of unobstructed use of the Buffer constructor, whose insecure default constructor increases the odds of memory leakage.

Details

Constructing a Buffer class with integer N creates a Buffer of length N with raw (not "zero-ed") memory.

In the following example, the first call would allocate 100 bytes of memory, while the second example will allocate the memory needed for the string "100":

// uninitialized Buffer of length 100
x = new Buffer(100);
// initialized Buffer with value of '100'
x = new Buffer('100');

bl's append function uses the default Buffer constructor as-is, making it easy to append uninitialized memory to an existing list. If the value of the buffer list is exposed to users, it may expose raw server side memory, potentially holding secrets, private data and code. This is a similar vulnerability to the infamous Heartbleed flaw in OpenSSL.

const BufferList = require('bl')

var bl = new BufferList()
bl.append(new Buffer('abcd'))
bl.append(new Buffer('efg'))
bl.append('100')
// appends a Buffer holding 100 bytes of uninitialized memory
bl.append(100)                     
bl.append(new Buffer('j'))

You can read more about the insecure Buffer behavior on our blog.

Similar vulnerabilities were discovered in request, mongoose, ws and sequelize.

Note This is vulnerable only for Node <=4

References

medium severity

Uninitialized Memory Exposure

  • Vulnerable module: tunnel-agent
  • Introduced through: azure-mgmt-storage@0.9.16 and falcor-router-demo@1.0.3

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d azure-mgmt-storage@0.9.16 azure-common@0.9.11 request@2.45.0 tunnel-agent@0.4.3
    Remediation: Open PR to patch tunnel-agent@0.4.3.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0 request@2.28.0 tunnel-agent@0.3.0
    Remediation: Upgrade to falcor-router-demo@1.0.5.

Overview

tunnel-agent is HTTP proxy tunneling agent. Affected versions of the package are vulnerable to Uninitialized Memory Exposure.

A possible memory disclosure vulnerability exists when a value of type number is used to set the proxy.auth option of a request request and results in a possible uninitialized memory exposures in the request body.

This is a result of unobstructed use of the Buffer constructor, whose insecure default constructor increases the odds of memory leakage.

Details

Constructing a Buffer class with integer N creates a Buffer of length N with raw (not "zero-ed") memory.

In the following example, the first call would allocate 100 bytes of memory, while the second example will allocate the memory needed for the string "100":

// uninitialized Buffer of length 100
x = new Buffer(100);
// initialized Buffer with value of '100'
x = new Buffer('100');

tunnel-agent's request construction uses the default Buffer constructor as-is, making it easy to append uninitialized memory to an existing list. If the value of the buffer list is exposed to users, it may expose raw server side memory, potentially holding secrets, private data and code. This is a similar vulnerability to the infamous Heartbleed flaw in OpenSSL.

Proof of concept by ChALkeR

require('request')({
  method: 'GET',
  uri: 'http://www.example.com',
  tunnel: true,
  proxy:{
      protocol: 'http:',
      host:"127.0.0.1",
      port:8080,
      auth:80
  }
});

You can read more about the insecure Buffer behavior on our blog.

Similar vulnerabilities were discovered in request, mongoose, ws and sequelize.

Remediation

Upgrade tunnel-agent to version 0.6.0 or higher. Note This is vulnerable only for Node <=4

References

low severity

CORS Bypass

  • Vulnerable module: hapi
  • Introduced through: hapi@10.5.0

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0
    Remediation: Upgrade to hapi@11.0.0.

Overview

Hapi v11.0.0 and below have an incorrect implementation of the CORS protocol, and allow for configurations that, at best, return inconsistent headers and, at worst, cross-origin activities that are expected to be forbidden.

Details

If the connection has CORS enabled but one route has it off, and the route is not GET, the OPTIONS prefetch request will return the default CORS headers and then the actual request will go through and return no CORS headers. This defeats the purpose of turning CORS on the route.

Remediation

Upgrade to a version 11.0.0 or greater.

References

low severity

Potentially loose security restrictions

  • Vulnerable module: hapi
  • Introduced through: hapi@10.5.0

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d hapi@10.5.0
    Remediation: Upgrade to hapi@11.1.4.

Overview

Security restrictions (e.g. origin) get overridden by less restrictive defaults (i.e. all origins) in cases when server level, connection level or route level CORS configurations are combined.

References

low severity

Regular Expression Denial of Service (DoS)

  • Vulnerable module: hawk
  • Introduced through: azure-mgmt-storage@0.9.16 and falcor-router-demo@1.0.3

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d azure-mgmt-storage@0.9.16 azure-common@0.9.11 request@2.45.0 hawk@1.1.1
    Remediation: Open PR to patch hawk@1.1.1.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0 request@2.28.0 hawk@1.0.0
    Remediation: Upgrade to falcor-router-demo@1.0.5.

Overview

hawk is an HTTP authentication scheme using a message authentication code (MAC) algorithm to provide partial HTTP request cryptographic verification.

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) attacks.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

You can read more about Regular Expression Denial of Service (ReDoS) on our blog.

References

low severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: mime
  • Introduced through: falcor-router-demo@1.0.3 and azure-mgmt-storage@0.9.16

Detailed paths

  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0 request@2.28.0 mime@1.2.11
    Remediation: Open PR to patch mime@1.2.11.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d azure-mgmt-storage@0.9.16 azure-common@0.9.11 request@2.45.0 form-data@0.1.4 mime@1.2.11
    Remediation: Open PR to patch mime@1.2.11.
  • Introduced through: snyk-demo-app@snyk/snyk-demo-app#2f31650f3fbdfac424cb54708a66550e7a8e4e0d falcor-router-demo@1.0.3 pouchdb@3.6.0 request@2.28.0 form-data@0.1.4 mime@1.2.11
    Remediation: Open PR to patch mime@1.2.11.

Overview

mime is a comprehensive, compact MIME type module.

Affected versions of this package are vulnerable to Regular expression Denial of Service (ReDoS). It uses regex the following regex /.*[\.\/\\]/ in its lookup, which can cause a slowdown of 2 seconds for 50k characters.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade mime to versions 1.4.1, 2.0.3 or higher.

References