Repudiation - not claiming responsibility for an action taken

  • 8 minutes

Repudiation occurs when someone, with or without malicious intent, takes an action but claims otherwise.

Examples include:

  • Denying the modification of logs containing sensitive actions.
  • Using someone else's account to avoid getting caught.
  • Claiming not to have deleted database records.

Note

System logs are a goldmine for an attacker, not just to manipulate, but also to gather data about users, environment, and weaknesses.

Elements and interactions at risk from repudiation attacks

Element

Name Shape Definition
Process Process. Activity that modifies or redirects input to an output
External entity External Entity. Process, data store, or even full-fledged applications outside your control
Data store Data Store. Permanent or temporary data storage

Interaction

Name Interaction Definition
Process <-> Process Process to Process Interaction. A task sends or receives data to or from another task
Process <-> External Entity Process to External Entity Interaction. A task sends or receives data to or from a user
Process <-> Data Store Process to Data Store Interaction. A task sends or receives data to or from a data store

How to prevent repudiation

Non-repudiation ensures each action can be traced back to its origin by creating and protecting security logs.

Common security controls to reduce or eliminate risk

  • Strong authentication
  • Secure logging and monitoring
  • Digital signatures
  • Secure timestamps
  • Trusted third parties

Tip

Good question to ask: Can I tie every action to an identity?

Check your knowledge

1.

Which statement describes a potential security control against repudiation?