A user performs a high volume financial transaction through a bank website; however after that action the user denies that he has performed the transaction. What threat classification does this scenario relate to?

Repudiation threats involve a user denying legitimate actions they performed. Non-repudiation mechanisms like digital signatures and audit logs provide evidence of transactions. Spoofing (A) is impersonation, tampering (B) is unauthorized modification, and DoS (D) disrupts availability. The scenario describes a classic repudiation risk where a user falsely denies executing a transaction.