Find, fix and prevent vulnerabilities in your code.

Overview

com.fasterxml.jackson.core:jackson-databind is a library which contains the general-purpose data-binding functionality and tree-model for Jackson Data Processor.

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in the _findDeserializer() method of TypeDeserializerBase, which caches every unknown type ID as a distinct key in the _deserializers map even when all of them resolve to the same defaultImpl fallback. An attacker can grow that cache without bound for the lifetime of the process, exhausting memory over time, by submitting a stream of novel type identifiers. This requires the application to use name-based polymorphism through @JsonTypeInfo(use = Id.NAME, defaultImpl = ...), to accept attacker-controlled type identifiers, and to reuse the mapper instance across requests.

Remediation

Upgrade com.fasterxml.jackson.core:jackson-databind to version 2.18.11, 2.21.7, 2.22.3 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Issue

Overview

com.fasterxml.jackson.core:jackson-databind is a library which contains the general-purpose data-binding functionality and tree-model for Jackson Data Processor.

Affected versions of this package are vulnerable to Improperly Controlled Modification of Dynamically-Determined Object Attributes in the BeanDeserializerBase.createContextual() method, which applies the per-property exclusions through _handleByNameInclusion() and then rebuilds the property map from the unfiltered original, overwriting the filtered map and restoring every property the exclusion had removed. An attacker can set fields that were marked ignored, enabling mass assignment, by supplying those property names in untrusted JSON during deserialization. Exploitation requires case-insensitive property matching to be enabled via @JsonFormat with ACCEPT_CASE_INSENSITIVE_PROPERTIES alongside per-property @JsonIgnoreProperties.

Remediation

Upgrade com.fasterxml.jackson.core:jackson-databind to version 2.18.9, 2.21.5, 2.22.1 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Issue
• GitHub Issue

Overview

com.fasterxml.jackson.core:jackson-databind is a library which contains the general-purpose data-binding functionality and tree-model for Jackson Data Processor.

Affected versions of this package are vulnerable to Improperly Controlled Modification of Dynamically-Determined Object Attributes in the POJOPropertiesCollector._removeUnwantedIgnorals process. An attacker can access or modify properties that were intended to be ignored by supplying JSON input with keys matching the renamed property names, thereby bypassing intended access restrictions.

Remediation

Upgrade com.fasterxml.jackson.core:jackson-databind to version 2.18.8, 2.21.4 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Commit
• GitHub PR

Overview

com.fasterxml.jackson.core:jackson-databind is a library which contains the general-purpose data-binding functionality and tree-model for Jackson Data Processor.

Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) in the JDKFromStringDeserializer class, which constructs InetSocketAddress and resolves the hostname through DNS at deserialization time. An attacker can force the server to issue outbound DNS lookups for chosen hostnames by submitting JSON that is deserialized into a type holding an InetSocketAddress field, with no authentication required. The observable effect is limited to DNS resolution of attacker-chosen names, useful for out-of-band interaction or internal resolver probing rather than a full outbound request, and it applies only where the application deserializes untrusted JSON into types containing such fields.

Remediation

Upgrade com.fasterxml.jackson.core:jackson-databind to version 2.18.8, 2.21.4 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub PR

Overview

com.fasterxml.jackson.core:jackson-databind is a library which contains the general-purpose data-binding functionality and tree-model for Jackson Data Processor.

Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) through the STD_INET_ADDRESS branch in FromStringDeserializer in src/main/java/com/fasterxml/jackson/databind/deser/std/FromStringDeserializer.java. An attacker can trigger outbound DNS lookups and blind SSRF behavior by supplying a hostname string in JSON that is deserialized into java.net.InetAddress. When application code binds untrusted input into an InetAddress field or type, the deserializer calls InetAddress.getByName(value) on the attacker-controlled string and resolves it before any application validation runs. This lets an attacker force DNS-based callbacks or probe internal hostnames, causing unwanted network egress and leaking resolver-visible information.

Remediation

Upgrade com.fasterxml.jackson.core:jackson-databind to version 2.18.9, 2.21.5, 2.22.1 or higher.

References

• GitHub Commit jackson-databind-2.21.1
• GitHub Commit jackson-databind-3.2.1
• Maintainer's Advisory

Overview

com.fasterxml.jackson.core:jackson-databind is a library which contains the general-purpose data-binding functionality and tree-model for Jackson Data Processor.

Affected versions of this package are vulnerable to Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection') through NioPathDeserializer in src/main/java/com/fasterxml/jackson/databind/ext/NioPathDeserializer.java. An attacker can force readValue() to resolve an attacker-controlled java.nio.file.Path URI by supplying a non-file scheme such as jar:, http:, s3:, or a custom provider scheme in untrusted JSON. That input reaches new URI(value) and then Path.of(uri), which falls back to ServiceLoader<FileSystemProvider> resolution and can invoke a matching provider’s getPath(uri) during deserialization. The result is unintended provider loading and provider-driven path handling inside the application, which can trigger denial of service or other side effects depending on what FileSystemProvider implementations are present on the classpath.

Remediation

Upgrade com.fasterxml.jackson.core:jackson-databind to version 2.18.10, 2.21.6, 2.22.2 or higher.

References

• GitHub Commit
• GitHub Commit
• GitHub Commit
• GitHub PR
• Maintainer's Advisory

Overview

commons-io:commons-io is a The Apache Commons IO library contains utility classes, stream implementations, file filters, file comparators, endian transformation classes, and much more.

Affected versions of this package are vulnerable to Uncontrolled Resource Consumption ('Resource Exhaustion') through the XmlStreamReader class. An attacker can cause the application to consume excessive CPU resources by sending specially crafted XML content.

Remediation

Upgrade commons-io:commons-io to version 2.14.0 or higher.

References

• Apache Advisory
• GitHub Commit

Overview

org.springframework:spring-core is a core package within the spring-framework that contains multiple classes and utilities.

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling via static resource resolution. An attacker can cause denial of service by sending crafted requests that are slow to resolve when accessing file-system-backed static resources, causing HTTP connections to remain occupied and exhausting server resources.

Note: This is only exploitable if all the following are true:

1. The application uses Spring MVC or Spring WebFlux.

2. Static resources are served from the file system.

3. The application is running on Windows.

Remediation

Upgrade org.springframework:spring-core to version 6.2.18, 7.0.7 or higher.

References

• GitHub Commit
• spring Security Advisory

Overview

Affected versions of this package are vulnerable to Exposed Dangerous Method or Function via Spring Expression Language (SpEL) method invocation handling. An attacker can invoke arbitrary zero-argument methods by supplying crafted SpEL expressions, even in contexts intended to restrict method execution or provide read-only access. This may allow execution of unintended application logic and access to functionality that should not be exposed through expression evaluation.

Note: This is only exploitable if the application accepts and evaluates untrusted or user-controlled SpEL expressions.

Remediation

Upgrade org.springframework:spring-expression to version 6.0.0, 6.2.19, 7.0.8 or higher.

References

• GitHub Commit
• GitHub Release
• GitHub Release
• Spring Security Advisory

Overview

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) in the PATTERN_FLOAT regex of NumberInput, reached through looksLikeValidNumber(), where adjacent quantifiers over the same character class ([0-9]*, then an optional [.], then [0-9]+) carry no possessive quantifiers or atomic grouping, so the engine explores every split point between digit groups on non-matching input. An attacker can pin a request-handling thread and exhaust the worker pool with concurrent requests by supplying a long numeric-looking string that fails to match, since match cost is quadratic in input length, with 160,000 characters costing 74.4 seconds in a single call. This requires the application to reach looksLikeValidNumber() with attacker-controlled strings, which is the default path when jackson-databind coerces a String field to a number, and the input is bounded only by StreamReadConstraints.maxStringLength at 20,000,000 rather than by maxNumberLength at 1,000.

Workaround

This vulnerability can be avoided by lowering StreamReadConstraints.maxStringLength toward the string length the application actually needs, which caps the input this quadratic path can be handed, since it is that limit and not maxNumberLength that governs here.

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.

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 tools.jackson.core:jackson-core to version 3.1.7, 3.2.2 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Commit
• GitHub Issue
• GitHub PR
• GitHub PR

Overview

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in the _findDeserializer() method of TypeDeserializerBase, which caches every unknown type ID as a distinct key in the _deserializers map even when all of them resolve to the same defaultImpl fallback. An attacker can grow that cache without bound for the lifetime of the process, exhausting memory over time, by submitting a stream of novel type identifiers. This requires the application to use name-based polymorphism through @JsonTypeInfo(use = Id.NAME, defaultImpl = ...), to accept attacker-controlled type identifiers, and to reuse the mapper instance across requests.

Remediation

Upgrade tools.jackson.core:jackson-databind to version 3.1.7, 3.2.3 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Issue

Overview

Affected versions of this package are vulnerable to Improperly Controlled Modification of Dynamically-Determined Object Attributes in the POJOPropertiesCollector._renameProperties() and BeanDeserializerFactory.addBeanProps() methods, which rename rather than drop a property whose getter carries @JsonProperty and whose setter carries @JsonIgnore, leaving the private backing field writable. An attacker can write a field that was meant to be unsettable, enabling property tampering and mass assignment, by supplying the renamed JSON key during deserialization, because the factory observes hasField()==true and builds a writable FieldProperty for the backing field. Exploitation requires MapperFeature.INFER_PROPERTY_MUTATORS to be enabled, which is the default, and a target type that pairs a renamed getter with an ignored setter, and the impact is limited to writing existing fields with no path to remote code execution.

Remediation

Upgrade tools.jackson.core:jackson-databind to version 3.1.4 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Commit
• GitHub PR
• GitHub PR

Overview

Affected versions of this package are vulnerable to Improperly Controlled Modification of Dynamically-Determined Object Attributes in the BeanDeserializerBase.createContextual() method, which applies the per-property exclusions through _handleByNameInclusion() and then rebuilds the property map from the unfiltered original, overwriting the filtered map and restoring every property the exclusion had removed. An attacker can set fields that were marked ignored, enabling mass assignment, by supplying those property names in untrusted JSON during deserialization. Exploitation requires case-insensitive property matching to be enabled via @JsonFormat with ACCEPT_CASE_INSENSITIVE_PROPERTIES alongside per-property @JsonIgnoreProperties.

Remediation

Upgrade tools.jackson.core:jackson-databind to version 3.1.4 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Issue
• GitHub Issue

Overview

Affected versions of this package are vulnerable to Improperly Controlled Modification of Dynamically-Determined Object Attributes in the POJOPropertiesCollector._removeUnwantedIgnorals process. An attacker can access or modify properties that were intended to be ignored by supplying JSON input with keys matching the renamed property names, thereby bypassing intended access restrictions.

Remediation

Upgrade tools.jackson.core:jackson-databind to version 3.1.4 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Commit
• GitHub PR

Overview

Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) in the JDKFromStringDeserializer class, which constructs InetSocketAddress and resolves the hostname through DNS at deserialization time. An attacker can force the server to issue outbound DNS lookups for chosen hostnames by submitting JSON that is deserialized into a type holding an InetSocketAddress field, with no authentication required. The observable effect is limited to DNS resolution of attacker-chosen names, useful for out-of-band interaction or internal resolver probing rather than a full outbound request, and it applies only where the application deserializes untrusted JSON into types containing such fields.

Remediation

Upgrade tools.jackson.core:jackson-databind to version 3.1.4 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub PR

Overview

Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) through the STD_INET_ADDRESS branch in FromStringDeserializer in src/main/java/com/fasterxml/jackson/databind/deser/std/FromStringDeserializer.java. An attacker can trigger outbound DNS lookups and blind SSRF behavior by supplying a hostname string in JSON that is deserialized into java.net.InetAddress. When application code binds untrusted input into an InetAddress field or type, the deserializer calls InetAddress.getByName(value) on the attacker-controlled string and resolves it before any application validation runs. This lets an attacker force DNS-based callbacks or probe internal hostnames, causing unwanted network egress and leaking resolver-visible information.

Remediation

Upgrade tools.jackson.core:jackson-databind to version 3.1.5, 3.2.1 or higher.

References

• GitHub Commit jackson-databind-2.21.1
• GitHub Commit jackson-databind-3.2.1
• Maintainer's Advisory

Overview

Affected versions of this package are vulnerable to Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection') through NioPathDeserializer in src/main/java/com/fasterxml/jackson/databind/ext/NioPathDeserializer.java. An attacker can force readValue() to resolve an attacker-controlled java.nio.file.Path URI by supplying a non-file scheme such as jar:, http:, s3:, or a custom provider scheme in untrusted JSON. That input reaches new URI(value) and then Path.of(uri), which falls back to ServiceLoader<FileSystemProvider> resolution and can invoke a matching provider’s getPath(uri) during deserialization. The result is unintended provider loading and provider-driven path handling inside the application, which can trigger denial of service or other side effects depending on what FileSystemProvider implementations are present on the classpath.

Remediation

Upgrade tools.jackson.core:jackson-databind to version 3.1.6, 3.2.2 or higher.

References

• GitHub Commit
• GitHub Commit
• GitHub Commit
• GitHub PR
• Maintainer's Advisory

Overview

com.fasterxml.jackson.core:jackson-databind is a library which contains the general-purpose data-binding functionality and tree-model for Jackson Data Processor.

Affected versions of this package are vulnerable to Deserialization of Untrusted Data in the isSafeSubType() method of DefaultBaseTypeLimitingValidator, whose denylist of unsafe base types omits java.lang.Comparable, so the method returns true for any subtype resolved under a Comparable base. An attacker can trigger instantiation of arbitrary classes that implement Comparable, such as java.io.File to reach path-traversal primitives, by sending JSON with attacker-controlled type identifiers. This requires the application to use a bare @JsonTypeInfo with the default validator and no explicit PolymorphicTypeValidator, and a property or class whose declared base type is Comparable.

Workaround

This vulnerability can be avoided by configuring an explicit restrictive PolymorphicTypeValidator, such as a BasicPolymorphicTypeValidator allowlist passed to activateDefaultTyping(), instead of relying on the default validator.

Note: The discoverer of this vulnerability reports that "I have not identified a class implementing Comparable that yields code execution purely through deserialization".

Details

Serialization is a process of converting an object into a sequence of bytes which can be persisted to a disk or database or can be sent through streams. The reverse process of creating object from sequence of bytes is called deserialization. Serialization is commonly used for communication (sharing objects between multiple hosts) and persistence (store the object state in a file or a database). It is an integral part of popular protocols like Remote Method Invocation (RMI), Java Management Extension (JMX), Java Messaging System (JMS), Action Message Format (AMF), Java Server Faces (JSF) ViewState, etc.

Deserialization of untrusted data (CWE-502) is when the application deserializes untrusted data without sufficiently verifying that the resulting data will be valid, thus allowing the attacker to control the state or the flow of the execution.

Remediation

Upgrade com.fasterxml.jackson.core:jackson-databind to version 2.18.10, 2.21.6, 2.22.2 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Issue
• GitHub PR

Overview

org.springframework:spring-core is a core package within the spring-framework that contains multiple classes and utilities.

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) via pattern processing in AntPathMatcher. An attacker can cause denial of service by supplying a crafted regular expression pattern to methods such as match(), matchStart(), or extractUriTemplateVariables(), triggering excessive backtracking and CPU consumption during pattern evaluation.

Note: This is only exploitable if attacker-controlled input is used directly or indirectly as the pattern argument to one of the affected AntPathMatcher methods.

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.

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 org.springframework:spring-core to version 6.0.0, 6.2.19, 7.0.8 or higher.

References

• GitHub Commit
• GitHub Release
• GitHub Release
• Spring Security Advisory

Overview

Affected versions of this package are vulnerable to Deserialization of Untrusted Data in the isSafeSubType() method of DefaultBaseTypeLimitingValidator, whose denylist of unsafe base types omits java.lang.Comparable, so the method returns true for any subtype resolved under a Comparable base. An attacker can trigger instantiation of arbitrary classes that implement Comparable, such as java.io.File to reach path-traversal primitives, by sending JSON with attacker-controlled type identifiers. This requires the application to use a bare @JsonTypeInfo with the default validator and no explicit PolymorphicTypeValidator, and a property or class whose declared base type is Comparable.

Workaround

This vulnerability can be avoided by configuring an explicit restrictive PolymorphicTypeValidator, such as a BasicPolymorphicTypeValidator allowlist passed to activateDefaultTyping(), instead of relying on the default validator.

Note: The discoverer of this vulnerability reports that "I have not identified a class implementing Comparable that yields code execution purely through deserialization".

Details

Serialization is a process of converting an object into a sequence of bytes which can be persisted to a disk or database or can be sent through streams. The reverse process of creating object from sequence of bytes is called deserialization. Serialization is commonly used for communication (sharing objects between multiple hosts) and persistence (store the object state in a file or a database). It is an integral part of popular protocols like Remote Method Invocation (RMI), Java Management Extension (JMX), Java Messaging System (JMS), Action Message Format (AMF), Java Server Faces (JSF) ViewState, etc.

Deserialization of untrusted data (CWE-502) is when the application deserializes untrusted data without sufficiently verifying that the resulting data will be valid, thus allowing the attacker to control the state or the flow of the execution.

Remediation

Upgrade tools.jackson.core:jackson-databind to version 3.1.6, 3.2.2 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Issue
• GitHub PR

Overview

com.google.guava:guava is a set of core libraries that includes new collection types (such as multimap and multiset,immutable collections, a graph library, functional types, an in-memory cache and more.

Affected versions of this package are vulnerable to Deserialization of Untrusted Data. During deserialization, two Guava classes accept a caller-specified size parameter and eagerly allocate an array of that size:

• AtomicDoubleArray (when serialized with Java serialization)
• CompoundOrdering (when serialized with GWT serialization)

An attacker may be able to send a specially crafted request which with then cause the server to allocate all it's memory, without validation whether the data size is reasonable.

Details

Serialization is a process of converting an object into a sequence of bytes which can be persisted to a disk or database or can be sent through streams. The reverse process of creating object from sequence of bytes is called deserialization. Serialization is commonly used for communication (sharing objects between multiple hosts) and persistence (store the object state in a file or a database). It is an integral part of popular protocols like Remote Method Invocation (RMI), Java Management Extension (JMX), Java Messaging System (JMS), Action Message Format (AMF), Java Server Faces (JSF) ViewState, etc.

Deserialization of untrusted data (CWE-502), is when the application deserializes untrusted data without sufficiently verifying that the resulting data will be valid, letting the attacker to control the state or the flow of the execution.

Java deserialization issues have been known for years. However, interest in the issue intensified greatly in 2015, when classes that could be abused to achieve remote code execution were found in a popular library (Apache Commons Collection). These classes were used in zero-days affecting IBM WebSphere, Oracle WebLogic and many other products.

An attacker just needs to identify a piece of software that has both a vulnerable class on its path, and performs deserialization on untrusted data. Then all they need to do is send the payload into the deserializer, getting the command executed.

Developers put too much trust in Java Object Serialization. Some even de-serialize objects pre-authentication. When deserializing an Object in Java you typically cast it to an expected type, and therefore Java's strict type system will ensure you only get valid object trees. Unfortunately, by the time the type checking happens, platform code has already created and executed significant logic. So, before the final type is checked a lot of code is executed from the readObject() methods of various objects, all of which is out of the developer's control. By combining the readObject() methods of various classes which are available on the classpath of the vulnerable application, an attacker can execute functions (including calling Runtime.exec() to execute local OS commands).

Remediation

Upgrade com.google.guava:guava to version 24.1.1, 24.1.1-jre or higher.

References

• GitHub Commit
• Google Group Forum
• RedHat Bugzilla Bug

Overview

commons-io:commons-io is a The Apache Commons IO library contains utility classes, stream implementations, file filters, file comparators, endian transformation classes, and much more.

Affected versions of this package are vulnerable to Directory Traversal via calling the method FileNameUtils.normalize using an improper string like //../foo or \\..\foo, which may allow access to files in the parent directory.

Details

A Directory Traversal attack (also known as path traversal) aims to access files and directories that are stored outside the intended folder. By manipulating files with "dot-dot-slash (../)" sequences and its variations, or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system, including application source code, configuration, and other critical system files.

Directory Traversal vulnerabilities can be generally divided into two types:

• Information Disclosure: Allows the attacker to gain information about the folder structure or read the contents of sensitive files on the system.

st is a module for serving static files on web pages, and contains a vulnerability of this type. In our example, we will serve files from the public route.

If an attacker requests the following URL from our server, it will in turn leak the sensitive private key of the root user.

curl http://localhost:8080/public/%2e%2e/%2e%2e/%2e%2e/%2e%2e/%2e%2e/root/.ssh/id_rsa

Note %2e is the URL encoded version of . (dot).

• Writing arbitrary files: Allows the attacker to create or replace existing files. This type of vulnerability is also known as Zip-Slip.

One way to achieve this is by using a malicious zip archive that holds path traversal filenames. When each filename in the zip archive gets concatenated to the target extraction folder, without validation, the final path ends up outside of the target folder. If an executable or a configuration file is overwritten with a file containing malicious code, the problem can turn into an arbitrary code execution issue quite easily.

The following is an example of a zip archive with one benign file and one malicious file. Extracting the malicious file will result in traversing out of the target folder, ending up in /root/.ssh/ overwriting the authorized_keys file:

2018-04-15 22:04:29 .....           19           19  good.txt
2018-04-15 22:04:42 .....           20           20  ../../../../../../root/.ssh/authorized_keys

Remediation

Upgrade commons-io:commons-io to version 2.7 or higher.

References

• GitHub Commit
• Jira Issue
• PoC

Overview

Affected versions of this package are vulnerable to Incorrect Authorization in the BeanDeserializer._deserializeUsingPropertyBased method, whose property-buffering branch omits the prop.visibleInView(activeView) check that the creator-property branch performs. An attacker can populate view-restricted setterless collection or map properties, such as admin-only fields, from untrusted JSON by supplying values for them during deserialization, bypassing @JsonView protection. This affects only setterless collection or map properties annotated with a restricted @JsonView and reached through the property-based creator path.

Remediation

Upgrade tools.jackson.core:jackson-databind to version 3.1.4 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Commit
• GitHub PR
• GitHub PR

Overview

Affected versions of this package are vulnerable to Incorrect Authorization in the UnwrappedPropertyHandler.processUnwrappedCreatorProperties() method, which replays buffered JSON into creator parameters without consulting prop.visibleInView(activeView). An attacker can set view-restricted constructor parameters annotated with both @JsonView and @JsonUnwrapped, such as admin-only fields, from untrusted JSON by supplying them during deserialization while a more restrictive view is active, defeating the @JsonView write-side authorization boundary.

Remediation

Upgrade tools.jackson.core:jackson-databind to version 3.1.4 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Commit
• GitHub PR
• GitHub PR

MPL-2.0 license