OAM_FAILURE_MODES.md

OAM Failure Modes

Secure Packet Transfer Integrity Stack v0.1

OAM is used here as a degradation and hard-fault diagnostic layer. It identifies where packet-transfer claims can fail under pressure.

Failure modes

1. Payload mismatch

The destination payload does not match the source payload under verification.

• Primary pressure: payload_fidelity_failure
• Likely state: RED
• Example signals: hash mismatch, corrupted payload, unexpected transform, partial transfer.

2. Replay pressure

Old, duplicated, or captured traffic is presented as valid.

• Primary pressure: replay_pressure
• Likely state: RED if detected or anti-replay protection fails.
• Example signals: reused nonce, invalid sequence, duplicate signed packet, timestamp anomaly.

3. Downgrade attempt

A stronger protocol, cipher suite, setting, or protection state is weakened without authorization.

• Primary pressure: downgrade_attempt
• Likely state: RED
• Example signals: negotiated weaker version, forced fallback, policy mismatch.

4. Man-in-the-middle pressure

An intermediary attempts to observe, alter, impersonate, or redirect the session.

• Primary pressure: mitm_pressure
• Likely state: RED when identity/session verification fails; YELLOW when unresolved anomaly remains.

5. Certificate / key failure

The transfer depends on identity material that is stale, invalid, revoked, mismatched, weak, compromised, or unverifiable.

• Primary pressure: certificate_failure or key_compromise
• Likely state: YELLOW or RED depending on policy and severity.

6. Route/session drift

The route or session behavior changes in a way that creates uncertainty or integrity pressure.

• Primary pressure: route_hijack or route_session_drift
• Likely state: YELLOW unless identity/session evidence fails, then RED.

7. Metadata leakage

Payload may remain protected while metadata leaks more than the boundary permits.

• Primary pressure: metadata_leakage
• Likely state: YELLOW or RED depending on sensitivity and policy.

8. Endpoint compromise

The transfer protocol succeeds, but one endpoint is degraded, malicious, or already compromised.

• Primary pressure: endpoint_compromise
• Likely state: RED if confirmed; YELLOW if suspected.

9. Audit-chain break

The evidence chain is incomplete, discontinuous, tampered, missing, or unverifiable.

• Primary pressure: audit_chain_break
• Likely state: RED or downgraded claim state.

OAM rule

A transfer cannot be upgraded beyond the evidence boundary. If audit continuity fails, claims must downgrade even when delivery appears successful.