Description

An adversary creates a serialized data file (e.g. XML, YAML, etc...) that contains an external data reference. Because serialized data parsers may not validate documents with external references, there may be no checks on the nature of the reference in the external data. This can allow an adversary to open arbitrary files or connections, which may further lead to the adversary gaining access to information on the system that they would normally be unable to obtain.

Prerequisites

The target must follow external data references without validating the validity of the reference target.

Mitigations

Configure the serialized data processor to only retrieve external entities from trusted sources.

Skills Required

[Low] To send serialized data messages with maliciously crafted schema.