Deserialization of Untrusted Data Affecting typo3/phar-stream-wrapper package, versions >=2.0.0, <2.1.1 >=3.0.0, <3.1.1

typo3/phar-stream-wrapper is a stream handler package for a popular content management system.

Affected versions of this package are vulnerable to Deserialization of Untrusted Data. PharMetaDataInterceptor is used to discover potential insecure serialized objects in the meta-data section of Phar archives. An attacker can abuse the Phar structure, which mishandles Phar stub parsing without actually invoking PHP’s native process. It's then possible to inject manipulated bundles that would to have been blocked by the mentioned PharMetaDataInterceptor.

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).

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.

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.

• GitHub Commit

• GitHub Issue

• TYPO3 Advisory