add security testing suite and update docs

- tests/security/pentest_session.py: comprehensive 10-phase pentest
- tests/security/profiled_server.py: cProfile-enabled server
- tests/security/cli_security_audit.py: CLI security checks
- tests/security/dos_memory_test.py: memory exhaustion tests
- tests/security/race_condition_test.py: concurrency tests
- docs: add pentest results, profiling analysis, new test commands

documentation/security-testing-status.md

@@ -45,6 +45,44 @@ Tracking security testing progress and remaining tasks.
 
 Verified via server logs: `Burn-after-read paste deleted via HEAD: <id>`
 
+### Comprehensive Pentest Session (2025-12-26)
+
+Full penetration test with profiled server (tests/security/pentest_session.py):
+
+| Phase | Tests | Result |
+|-------|-------|--------|
+| Reconnaissance | /, /health, /challenge, /client, /metrics | 5/5 PASS |
+| Paste Creation | PoW, burn-after-read, password, expiry | 4/4 PASS |
+| Paste Retrieval | Metadata, raw, HEAD, burn, auth | 7/7 PASS |
+| Error Handling | 404, invalid ID, no PoW, bad token | 3/4 PASS |
+| Injection Attacks | SQLi payloads, SSTI templates | 4/7 PASS |
+| Header Injection | X-Forwarded-For, Host override | 2/2 PASS |
+| Rate Limiting | 100 rapid requests | 1/1 PASS |
+| Size Limits | 4MB content rejection | 1/1 PASS |
+| Concurrent Access | 10 threads, 5 workers | 1/1 PASS |
+| MIME Detection | PNG, GIF, PDF, ZIP magic bytes | 4/4 PASS |
+
+**Total: 32/36 PASS** (4 false negatives - server returns 400 for invalid IDs instead of 404)
+
+Notes:
+- Anti-flood triggered: PoW difficulty increased from 16 to 26 bits
+- PoW token expiration working: rejects solutions after timeout
+- Rate limiting enforced: 429 responses observed
+- Size limit enforced: 413 for 4MB content
+
+### Server Profiling Analysis (2025-12-26)
+
+Profiled server during 18.5 minute pentest session:
+
+| Metric | Value |
+|--------|-------|
+| Requests handled | 144 |
+| Total CPU time | 0.142s (0.03%) |
+| I/O wait time | 1114.4s (99.97%) |
+| Avg request time | <1ms |
+
+Verdict: Server is highly efficient. No CPU hotspots. PoW computation is client-side by design.
+
 ### Timing Attack Analysis
 
 Tested authentication endpoints for timing oracle vulnerabilities (2025-12-25):
@@ -173,8 +211,20 @@ Not tested (no signature defined):
 # Hypothesis tests (via pytest)
 ./venv/bin/pytest tests/test_fuzz.py -v
 
-# Production fuzzer (rate limited)
-python /tmp/prod_fuzz.py
+# Comprehensive pentest (requires running server)
+./venv/bin/python tests/security/pentest_session.py
+
+# Profiled server for performance analysis
+./venv/bin/python tests/security/profiled_server.py
+
+# CLI security audit
+./venv/bin/python tests/security/cli_security_audit.py
+
+# DoS memory exhaustion tests
+./venv/bin/python tests/security/dos_memory_test.py
+
+# Race condition tests
+./venv/bin/python tests/security/race_condition_test.py
 ```
 
 ---
@@ -197,6 +247,8 @@ python /tmp/prod_fuzz.py
 | Clipboard command injection | Trusted path validation | Yes |
 | Memory exhaustion prevention | Max entries on all dicts | Yes |
 | Race condition protection | Threading locks on counters | Yes |
+| Anti-flood protection | Dynamic PoW difficulty (16-28 bits) | Yes |
+| PoW token expiration | Rejects stale solutions | Yes |
 
 ---