CAPEC-485: Signature Spoofing by Key Recreation

Description
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.
Extended Description

Signature verification algorithms are generally used to determine whether a certificate or piece of code (e.g. executable, binary, etc.) possesses a valid signature and can be trusted.

If the leveraged algorithm confirms that a valid signature exists, it establishes a foundation of trust that is further conveyed to the end-user when interacting with a website or application. However, if the signature verification algorithm improperly validates the signature, either by not validating the signature at all or by failing to fully validate the signature, it could result in an adversary generating a spoofed signature and being classified as a legitimate entity. Successfully exploiting such a weakness could further allow the adversary to reroute users to malicious sites, steals files, activates microphones, records keystrokes and passwords, wipes disks, installs malware, and more.

Severity :

High

Possibility :

Low

Type :

Detailed
Relationships with other CAPECs

This table shows the other attack patterns and high level categories that are related to this attack pattern.

Prerequisites

This table shows the other attack patterns and high level categories that are related to this attack pattern.

  • 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

This table shows the other attack patterns and high level categories that are related to this attack pattern.

  • 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.
Taxonomy mappings

Mappings to ATT&CK, OWASP and other frameworks.

Related CWE

A Related Weakness relationship associates a weakness with this attack pattern. Each association implies a weakness that must exist for a given attack to be successful.

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