Umbra Wiki attack-pattern attack-pattern/CAPEC-477
Back to wiki

CAPEC-477 — Signature Spoofing by Mixing Signed and Unsigned Content

provenance: imported · CWE: CWE-311 CWE-319 CWE-693

CAPEC-477: Signature Spoofing by Mixing Signed and Unsigned Content

MITRE CAPEC attack pattern

Status Draft
Typical severity High
Likelihood of attack Low
Catalogue CAPEC 3.9 (2023-01-24)

Description

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.

Where this sits in the chain

A finding maps to a weakness (CWE), a weakness is exploited by an attack pattern (CAPEC), and an attack pattern shows up in ATT&CK as observed adversary behaviour. This page is the middle hop.

Weaknesses exploited: CWE-311, CWE-319, CWE-693

Prerequisites

  • 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.

Skills required

  • 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.

Mitigations

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

Source