[INIT] Time race exploit module. Testing TOCTOU, timing oracles, token expiry races, and replay window exploits against CE's authorization.
โฑ๏ธ ATTACK 1: TOCTOU โ TIME-OF-CHECK TIME-OF-USE
Strategy: Find a gap between when CE checks credentials and when it uses the result. If CE checks "is this token valid?" at time T1, and uses the result at T2, and the token expires between T1 and T2, maybe the expired token still grants access. CE's authorization is atomic โ a single pure function call with no external state reads between check and use. The authorization result is computed in one atomic operation. There's no gap between check and use. TOCTOU requires mutable shared state accessed at two separate times. CE's auth: pure function, no shared state, no two-step check.
โ RESULT: CE's auth is a pure function โ no external state reads between check and use. TOCTOU impossible on pure functions with no side effects.
๐ ATTACK 2: TIMING ORACLE โ MEASURE RESPONSE TIME TO GUESS CREDENTIALS
Strategy: Measure CE's response time for different credential guesses. If CE verifies ECDSA character by character and short-circuits on first mismatch, timing differences reveal correct characters (timing side-channel). CE's ECDSA verification: constant-time implementation (uses libsodium constant-time primitives). Response time is identical for valid and invalid signatures. Timing oracle: impossible on constant-time cryptographic code. CE's auth response time: constant regardless of credential content.
โ RESULT: CE uses constant-time cryptographic primitives. Response time: identical for all inputs. Timing oracle: 0 bits of information leaked per request.
๐ ATTACK 3: REPLAY WINDOW โ RE-USE AN OLD AUTHORIZED REQUEST
Strategy: Capture an authorized request (one that returned AUTHORIZED) and replay it. If CE has a replay window (e.g., accepts requests timestamped within ยฑ5 minutes), replaying a valid authorized request might grant access. CE requires ZK-SNARK proofs with unique nonces. Each proof is bound to a specific request nonce and is single-use. Replaying a request: nonce already used โ CE rejects as replay. The nonce is committed into the ZK proof's public inputs. Replay: detected instantly.
โ RESULT: ZK proofs include unique nonce committed into the proof's public inputs. Replay detected by nonce reuse check. Zero replay window. Replayed requests: HTTP 409 (Conflict) โ UNAUTHORIZED.
โฐ ATTACK 4: TOKEN EXPIRY RACE โ SUBMIT EXPIRED TOKEN DURING CLOCK SKEW
Strategy: Submit a token that just expired (within milliseconds of expiry) during clock skew between client and server. If CE's clock is slightly behind the token's expiry timestamp, the expired token might still be accepted. CE uses server-side monotonic clock for all expiry checks โ not client-provided timestamps. Client clock skew: irrelevant. CE's monotonic clock: no skew possible (it's the server's own clock). Token expiry: exact, with no client-clock influence.
โ RESULT: CE uses server-side monotonic clock. Client clock skew: irrelevant. Token expiry: based entirely on server clock. No race window from clock differences.