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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

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 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

commons-collections:commons-collections is a library which contains types that extend and augment the Java Collections Framework.

Affected versions of this package are vulnerable to Deserialization of Untrusted Data. Versions of commons-collections prior to 3.2.2 do not prevent deserialization of the class org.apache.commons.collections.functors.InvokerTransformer. This could be leveraged by an attacker as a gadget within a vulnerable application which deserializes user input to execute arbitrary code.

Versions of commons-collections from 3.2.2 onwards will throw an UnsupportedOperationException error when attempts are made to deserialize InvokerTransformer instances to prevent potential remote code execution exploits.

Note: org.apache.commons:commons-collections is no longer supported and has been moved to org.apache.commons:commons-collections4 we recommend moving to the new artifact if possible.

PoC

/*
    Gadget chain:
        ObjectInputStream.readObject()
            AnnotationInvocationHandler.readObject()
                Map(Proxy).entrySet()
                    AnnotationInvocationHandler.invoke()
                        LazyMap.get()
                            ChainedTransformer.transform()
                                ConstantTransformer.transform()
                                InvokerTransformer.transform()
                                    Method.invoke()
                                        Class.getMethod()
                                InvokerTransformer.transform()
                                    Method.invoke()
                                        Runtime.getRuntime()
                                InvokerTransformer.transform()
                                    Method.invoke()
                                        Runtime.exec()
    Requires:
        commons-collections
 */

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).

• Apache Blog

The vulnerability, also know as Mad Gadget

Mad Gadget is one of the most pernicious vulnerabilities we’ve seen. By merely existing on the Java classpath, seven “gadget” classes in Apache Commons Collections (versions 3.0, 3.1, 3.2, 3.2.1, and 4.0) make object deserialization for the entire JVM process Turing complete with an exec function. Since many business applications use object deserialization to send messages across the network, it would be like hiring a bank teller who was trained to hand over all the money in the vault if asked to do so politely, and then entrusting that teller with the key. The only thing that would keep a bank safe in such a circumstance is that most people wouldn’t consider asking such a question.

• Google

Remediation

Upgrade commons-collections:commons-collections to version 3.2.2 or higher.

References

• GitHub Commit

• GitHub PR

• Jira Ticket

Overview

org.apache.httpcomponents:httpclient is an HttpClient component of the Apache HttpComponents project.

Affected versions of this package are vulnerable to Man-in-the-Middle (MitM) due to not verify the requesting server's hostname against existing domain names in the SSL Certificate.

The AbstractVerifier does not properly verify that the server hostname matches a domain name in the subject's Common Name (CN) or subjectAltName field of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via a "CN=" string in a field in the distinguished name (DN) of a certificate, as demonstrated by the "foo,CN=www.apache.org" string in the O field.

Details

Remediation

Upgrade org.apache.httpcomponents:httpclient to version 4.3.4 or higher.

References

• GitHub Commit

• NVD

• POC: Potential Exploit

• RedHat Bugzilla Bug

• SVN Revision Introducing Vuln

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

org.apache.httpcomponents:httpclient is a HttpClient component of the Apache HttpComponents project.

Affected versions of this package are vulnerable to Directory Traversal. String input by user is not validated for the presence of leading character / and is passed to the constructor as path information, resulting in a Directory Traversal vulnerability.

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 org.apache.httpcomponents:httpclient to version 4.5.3 or higher.

References

• GitHub Commit

• Jira Issue

• Researcher blog post

Overview

org.apache.httpcomponents:httpclient is a HttpClient component of the Apache HttpComponents project.

Affected versions of this package are vulnerable to Improper Input Validation. Apache HttpClient can misinterpret malformed authority component in request URIs passed to the library as java.net.URI object and pick the wrong target host for request execution.

Remediation

Upgrade org.apache.httpcomponents:httpclient to version 4.5.13 or higher.

References

• Apache Security Advisory
• GitHub Commit
• GitHub Commit

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.apache.httpcomponents:httpclient Apache HttpClient 4.x before 4.1.1 in Apache HttpComponents, when used with an authenticating proxy server, sends the Proxy-Authorization header to the origin server, which allows remote web servers to obtain sensitive information by logging this header.

References

• NVD

Overview

org.apache.httpcomponents:httpclient is a HttpClient component of the Apache HttpComponents project.

Affected versions of this package are vulnerable to Man-in-the-Middle (MitM) due to not verifing the requesting server's hostname agains existing domain names in the SSL Certificate. The AbstractVerifier does not properly verify that the server hostname matches a domain name in the subject's Common Name (CN) or subjectAltName field of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via a certificate with a subject that specifies a common name in a field that is not the CN field.

NOTE: this issue exists because of an incomplete fix for CVE-2012-5783.

Remediation

Upgrade org.apache.httpcomponents:httpclient to version 4.2.3 or higher.

References

• GitHub Commit
• NVD

Dual license: EPL-1.0, LGPL-2.1

Dual license: EPL-1.0, LGPL-2.1

EPL-1.0 license

EPL-1.0 license