COMMON ATTACK PATTERN ENUMERATION AND CLASSIFICATIONLive MITRE record

CAPEC-485

Signature Spoofing by Key Recreation

An attacker obtains an authoritative or reputable signer's private signature key by exploiting a cryptographic weakness in the signature algorithm or pseudorandom number generation and then uses this key to forge signatures from the original signer to mislead a victim into performing actions that benefit the attacker.

Abstraction

Detailed

Typical severity

High

Likelihood of attack

Low

Understand the attack

What is this attack pattern?

An attacker obtains an authoritative or reputable signer's private signature key by exploiting a cryptographic weakness in the signature algorithm or pseudorandom number generation and then uses this key to forge signatures from the original signer to mislead a victim into performing actions that benefit the attacker.

Requirements

What does the attack require?

Prerequisites

  • An authoritative signer is using a weak method of random number generation or weak signing software that causes key leakage or permits key inference.
  • An authoritative signer is using a signature algorithm with a direct weakness or with poorly chosen parameters that enable the key to be recovered using signatures from that signer.

Skills required

  • High: Cryptanalysis of signature generation algorithm
  • High: Reverse engineering and cryptanalysis of signature generation algorithm implementation and random number generation
  • High: Ability to create malformed data blobs and know how to present them directly or indirectly to a victim.

Resources required

Not stated in the MITRE record.

Defence

How is it prevented and mitigated?

1
Ensure cryptographic elements have been sufficiently tested for weaknesses.