Deserialization of Untrusted Data Affecting log4j:log4j package, versions [0,]

log4j:log4j is a 1.x branch of the Apache Log4j project. Note: Log4j 1.x reached End of Life in 2015, and is no longer supported.

Affected versions of this package are vulnerable to Deserialization of Untrusted Data. JMSSink in all versions of Log4j 1.x is vulnerable to deserialization of untrusted data when the attacker has write access to the Log4j configuration or if the configuration references an LDAP service the attacker has access to. The attacker can provide a TopicConnectionFactoryBindingName configuration causing JMSSink to perform JNDI requests that result in remote code execution in a similar fashion to CVE-2021-4104.

Note: this issue only affects Log4j 1.x when specifically configured to use JMSSink, which is not the default.

Apache Log4j 1.2 reached end of life in August 2015. Users should upgrade to Log4j 2 as it addresses numerous other issues from the previous versions.

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.

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