Malicious Signature

Overview

A malicious signature is a cryptographic signature obtained or created for an action that the signer did not understand, did not intend, or was deceived into authorizing.

Malicious Signature is closely connected to Permit Phishing, Private Key Compromise, and Hardware Security Key. The signature can be mathematically valid while the underlying approval is unsafe; cryptographic validity does not prove informed consent, trustworthy context, or legitimate transaction purpose.

Operational implementation should display human-readable intent, bind signatures to domain and chain, simulate effects, warn on broad approvals, verify counterparties, require policy approval for sensitive actions, and log the exact payload shown to the signer.

The principal failure modes include blind signing, phishing interfaces, malicious contract approvals, replayable messages, domain confusion, compromised devices, and signatures used outside the expected context.

Useful measures include blind-signing rate, dangerous approval warnings, simulation failures, signature-replay attempts, and confirmed losses from deceptive signing.

Operationally, teams should display human-readable intent, bind signatures to domain and chain, simulate effects, and warn on broad approvals. Key risks include blind signing, phishing interfaces, malicious contract approvals, and replayable messages.

A production treatment of Malicious Signature should test a cryptographic signature obtained or created for an action that the signer did not understand, did not intend, or was deceived into authorizing within the relevant asset, decision, or service state. The Malicious Signature context record for cryptographic signature obtained, did not intend, and was deceived into authorizing should preserve source data, configuration or policy version, responsible actor, exception, and outcome. Review of Malicious Signature should determine whether safeguards addressing cryptographic signature obtained, did not intend, and was deceived into authorizing changed exposure in practice, not merely whether a document or setting existed.