CAPEC-477 Signature Spoofing by Mixing Signed and Unsigned Content

An attacker exploits the underlying complexity of a data structure that allows for both signed and unsigned content, to cause unsigned data to be processed as though it were signed data.

• Signer and recipient are using complex data storage structures that allow for a mix between signed and unsigned data • Recipient is using signature verification software that does not maintain separation between signed and unsigned data once the signature has been verified.

• [High] The attacker may need to continuously monitor a stream of signed data, waiting for an exploitable message to appear. • [High] Attacker must be able to create malformed data blobs and know how to insert them in a location that the recipient will visit.

• Ensure the application is fully patched and does not allow the processing of unsigned data as if it is signed data.