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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.yaml:snakeyaml is a YAML 1.1 parser and emitter for Java.

Affected versions of this package are vulnerable to Arbitrary Code Execution in the Constructor class, which does not restrict which types can be deserialized. This vulnerability is exploitable by an attacker who provides a malicious YAML file for deserialization, which circumvents the SafeConstructor class.

The maintainers of the library contend that the application's trust would already have had to be compromised or established and therefore dispute the risk associated with this issue on the basis that there is a high bar for exploitation.

Remediation

Upgrade org.yaml:snakeyaml to version 2.0 or higher.

References

• BitBucket Changelog
• Bitbucket Commit
• Bitbucket Issue
• BitBucket Issue
• BitBucket PR
• BitBucket PR
• PoC
• Snyk Blog - Technical Deepdive
• Vulnerable Class

Overview

Affected versions of this package are vulnerable to Deserialization of Untrusted Data via the writeReplace() method in internal classes, which may allow a denial of service attack if combined with another exploit.

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.code.gson:gson to version 2.8.9 or higher.

References

• GitHub Commit Introducing Vulnerable Method
• GitHub Fix Commit
• GitHub PR

Overview

ch.qos.logback:logback-classic is a reliable, generic, fast and flexible logging library for Java.

Affected versions of this package are vulnerable to Improper Neutralization of Special Elements via the JaninoEventEvaluator extension. An attacker can execute arbitrary code by compromising an existing logback configuration file or injecting an environment variable before program execution.

Remediation

Upgrade ch.qos.logback:logback-classic to version 1.3.15, 1.5.13 or higher.

References

• Additional Information
• GitHub Commit
• GitHub Commit
• Release Notes

Overview

ch.qos.logback:logback-core is a logback-core module.

Affected versions of this package are vulnerable to External Initialization of Trusted Variables or Data Stores via the conditional processing of the logback.xml configuration file when both the Janino library and Spring Framework are present on the class path. An attacker can execute arbitrary code by compromising an existing configuration file or injecting a malicious environment variable before program execution. This is only exploitable if the attacker has write access to a configuration file or can set a malicious environment variable.

Remediation

Upgrade ch.qos.logback:logback-core to version 1.5.19 or higher.

References

• GitHub Commit
• Release Notes

Overview

ch.qos.logback:logback-core is a logback-core module.

Affected versions of this package are vulnerable to Improper Neutralization of Special Elements via the JaninoEventEvaluator extension. An attacker can execute arbitrary code by compromising an existing logback configuration file or injecting an environment variable before program execution.

Remediation

Upgrade ch.qos.logback:logback-core to version 1.3.15, 1.5.13 or higher.

References

• Additional Information
• GitHub Commit
• GitHub Commit
• Release Notes

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

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 Multipart Content Pollution. It provides client-side support for multipart requests. When the server application (server A) receives input from a remote client, and then uses that input to make a multipart request to another server (server B), it can be exposed to an attack, where an extra multipart is inserted in the content of the request from server A, causing server B to use the wrong value for a part it expects. This could to lead privilege escalation, for example, if the part content represents a username or user roles.

Remediation

Upgrade org.springframework:spring-core to version 4.3.14.RELEASE, 5.0.5.RELEASE or higher.

References

• GitHub Commit
• GitHub Commit
• NVD
• Pivotal Security Advisory

Overview

org.yaml:snakeyaml is a YAML 1.1 parser and emitter for Java.

Affected versions of this package are vulnerable to Denial of Service (DoS). The Alias feature in SnakeYAML 1.18 allows entity expansion during a load operation, a related issue to CVE-2003-1564.

Note While the Maintainer acknowledges the existence of the issue, they believe it should be solved by sanitizing the inputStream to the parser

Details

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

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

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

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

Two common types of DoS vulnerabilities:

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

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

Remediation

Upgrade org.yaml:snakeyaml to version 1.26 or higher.

References

• Bitbucket Commit
• Maintainer Report
• POC: Bitbucket Issue
• Proof Of Concept

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

ch.qos.logback:logback-core is a logback-core module.

Affected versions of this package are vulnerable to Insufficient Hostname Verification. X.509 are not properly validated. By spoofing the TLS/SSL server via a certificate that appears valid, an attacker with the ability to intercept network traffic (e.g. MitM, DNS cache poisoning) can disclose and optionally manipulate transmitted data.

Remediation

Upgrade ch.qos.logback:logback-core to version 1.2.7 or higher.

References

• GitHub Commit
• GitHub PR
• Jira Issue

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 Improper Input Validation when a user provides malicious input, causing insertion of additional log entries.

Remediation

Upgrade org.springframework:spring-core to version 5.2.19.RELEASE, 5.3.14 or higher.

References

• Pivotal Security Advisory

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 Improper Output Neutralization for Logs when a user provides malicious input, causing insertion of additional log entries.

Remediation

Upgrade org.springframework:spring-core to version 5.3.12, 5.2.18 or higher.

References

• Github Commit
• Pivotal Security Advisory

Overview

org.yaml:snakeyaml is a YAML 1.1 parser and emitter for Java.

Affected versions of this package are vulnerable to Stack-based Buffer Overflow when parsing crafted untrusted YAML files, which can lead to a denial-of-service.

Remediation

Upgrade org.yaml:snakeyaml to version 1.31 or higher.

References

• Bitbucket Commit
• Bitbucket Issue
• Chromium Bugs

Dual license: EPL-1.0, LGPL-2.1

Dual license: EPL-1.0, LGPL-2.1