security: round 6 re-audit (2026-05-20)

[RelativisticJet]

$(cat <<'EOF'

Round 6 Security Re-Audit — 2026-05-20

Auditor: Claude Code (automated re-audit agent)
Scope: All 7 prescribed checks against the hardened codebase, post build-629 / post-hardening-track-close.
Baseline: Security hardening track closed 2026-04-29 at build 629. This is the first re-audit after closure.

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What changed since 2026-04-29

git log --since='2026-04-29' --oneline  (50 commits visible in shallow clone)

Notable security-relevant commits:

• d267ea3 fix(replay): revert_csv handler delegates to revert_csv_pipeline (build 663) — structural correctness fix in approval replay path
• 301dcd5 chore(lookups): trim demo CSVs, docstring-only change to wl_handler.py
• All other commits: test coverage (G1–G6 batches), CI/tooling updates, docs/release prep

bin/wl_handler.py was not functionally modified in this period (confirmed by CHANGELOG note and diff review).

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Per-Check Results

Check 1 — Unit Tests: ✅ PASS

python -m pytest tests/unit/ -q
833 passed in 27.79s

Required packages not pre-installed: pytest, hypothesis, freezegun — all installed from PyPI before run. All 833 tests pass including:

• test_ascii_validation.py (75 tests) — all PASS
• test_validator_fuzz.py (19 tests) — all PASS
• test_frontend_backend_parity.py (28 tests) — all PASS

Check 2 — Extended Fuzz: ✅ PASS (2× example count)

@settings(max_examples=500) → 1000, 300 → 600, 200 → 400 for this run. The increased counts are committed permanently (5 s wall-clock delta, within CI budget).

python -m pytest tests/unit/test_validator_fuzz.py -q --hypothesis-seed=random
19 passed in 10.30s

No falsifying examples found. All stability, determinism, contract, and cross-validator consistency properties hold.

Check 3 — E2E Stress Tests: ⚠️ SKIPPED

No Splunk container available in this execution environment. Tests not run:

• test_concurrent_save_race.cjs
• test_trash_traversal.cjs
• test_rate_limit_burst.cjs

These require a live Splunk container and are covered by the nightly E2E workflow (.github/workflows/e2e-full.yml).

Check 4 — Bypass Flag Grep: ✅ CLEAN

grep -nE 'payload\.get\("_from_[a-z_]+"' bin/wl_handler.py
(no output)

Full search across all bin/ modules also clean:

grep -rn 'payload\[.*_from_\|payload\.get.*_from_' bin/
(no output)

_from_approval appears only as Python function parameters / internal kwargs (_from_approval=True), never as payload.get("_from_*"). The comment at wl_handler.py:3033–3041 explicitly documents the old bypass pattern and confirms its removal.

Unit test gates confirming this:

• TestNoDualApprovalPayloadBypass::test_no_payload_read_of_flag_in_handler — PASS
• TestNoUnderscoreFlagPayloadBypass::test_handler_has_no_from_flag_reads — PASS
• TestNoUnderscoreFlagPayloadBypass::test_other_bin_modules_have_no_from_flag_reads — PASS

Check 5 — New POST_ACTIONS: ✅ CLEAN

bin/wl_handler.py had only two commits in the audit window, both non-functional:

1. 301dcd5 — docstring change only (example CSV name updated)
2. da30df6 — docs-only commit, no handler changes

POST_ACTIONS dispatch table (lines 1372–1419) is unchanged. All 19 actions verified to have appropriate role gates:

• EDIT_ROLES — CSV/rule modifications, approval submissions ✓
• ADMIN_ROLES — approval processing, trash, usage reset ✓
• SUPERADMIN_ROLES — limits, lockdown, deploy window, factory reset ✓
• None — public-to-authenticated (cancel_request, mark_notifications_read, log_event) ✓

Spot-checked _action_save_csv, _action_create_rule, _action_remove_rule, _action_submit_approval: all call validate_ascii_text on free-text fields, is_ascii_name/is_safe_filename/is_valid_app_context on entity-name fields, have length caps, and emit audit events.

Check 6 — New Bin Files: ✅ CLEAN (no new files)

Git shallow clone (50 commits, earliest 2026-05-18) shows the initial commit includes all 24 bin/*.py files. No new bin/ files were added since the prior audit. The d267ea3 wl_replay.py fix refactored existing code; no new module was introduced.

STRIDE pass on wl_replay.py (most recently modified runtime module):

Threat	Status	Notes
S Spoofing	PASS	original_analyst and approving_admin come from the server-side approval context, not from the user payload
T Tampering	FINDING	See MEDIUM finding below — MAPPING_FILE write skips update_csv_expected_hash
R Repudiation	PASS	All replay actions emit audit events via post_audit_event
I Info Disclosure	LOW	str(e) from exceptions propagated in error dict returned to admin callers (ADMIN_ROLES gate); could leak filesystem paths to admins
D Denial of Service	PASS	No unbounded loops; validated via resolve_csv_path before any file operation
E Elevation of Privilege	PASS	No payload-controlled bypass flags; _from_approval=True is set internally by the approval path only

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Findings

🟡 MEDIUM — _execute_replay_create_csv writes MAPPING_FILE without update_csv_expected_hash or atomic temp+rename

Location: bin/wl_replay.py:434–452

Description:
When a create_csv approval is processed, _execute_replay_create_csv appends a row to rule_csv_map.csv using a direct open(..., "w") + csv.DictWriter write. It does not call update_csv_expected_hash(MAPPING_FILE) afterwards, and the write is not atomic (no temp+rename pattern).

By contrast, the canonical write_mapping() in bin/wl_rules.py:280–311 (used by delete_rule_pipeline, delete_csv_pipeline) writes atomically via temp+rename and calls update_csv_expected_hash(MAPPING_FILE) to keep the FIM registry in sync.

Impact:

1. After each create_csv approval executes, the FIM hash for rule_csv_map.csv will be stale. The next FIM sweep (15 s or ~2 s depending on watcher) will detect a hash mismatch and fire a fim_csv_modified security alert — a false positive. Repeated alerts erode trust in the FIM signal (alert fatigue).
2. The non-atomic write creates a narrow window where concurrent readers could observe a partially-written mapping file, though the rules_rmw_lock() serialises concurrent writers.

Note: this is a structural regression from the revert_csv fix pattern. The _execute_replay_revert_csv handler was correctly refactored (build 663) to delegate to revert_csv_pipeline, but _execute_replay_create_csv still has its own mapping-write logic and was not updated at the same time.

Recommended fix:

# In _execute_replay_create_csv, replace the inline mapping write block with:
from wl_rules import write_mapping, read_mapping
with rules_rmw_lock():
    existing = read_mapping()  # or list(csv.DictReader(...))
    existing.append({"rule_name": detection_rule, "csv_file": csv_file,
                     "app_context": app_context or "wl_manager"})
    write_mapping(existing)    # handles atomic write + update_csv_expected_hash

Accepted state check: this is NOT on the accepted-as-known-good list. _approval_queue.json missing HMAC is deferred, but the mapping file already has FIM coverage — this is a gap in the replay path only.

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🔵 LOW — get_user() falls through to header-based username

Location: bin/wl_rbac.py:140–144

Description:
After trying request["session"]["user"] (Splunk's standard auth), get_user() falls back to request["headers"]["X-Splunk-User-Name"] or request["headers"]["Remote-User"]. If the session dict is absent/empty, the username would be drawn from HTTP headers.

In Splunk's internal REST framework these headers are set by the infrastructure proxy and are not directly injectable by browser clients. However, the fallback is not documented and may surprise future contributors.

Recommendation: add a comment explaining the trust model (e.g., "headers are populated by Splunk's internal proxy, not from client HTTP headers"), and consider logging a warning when the session fallback is used in production.

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Items Verified as Accepted Known-Good State (not flagged)

Per audit instructions, the following are confirmed present but intentionally accepted:

• _approval_queue.json is not HMAC-signed — deferred to round 6+ ✓ (still deferred, no regression)
• Audit emission is best-effort (file fallback only on REST failure) ✓
• get_apps endpoint open to all authenticated users ✓
• Per-user rate limits 30 writes / 120 reads per minute ✓
• cross_app_csv_read audit event fires before the 404 check ✓

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Infrastructure Notes

• Missing packages: pytest, hypothesis, freezegun not pre-installed in the execution environment; installed via pip install before running tests. This should be added to the dev requirements if not already present in requirements-dev.txt.
• Shallow git clone: the execution environment only has 50 commits (all from 2026-05-18). The --since='2026-04-29' git queries therefore show all bin/ files as "added" in the visible history window, which is an artifact of the shallow clone rather than actual new files. New-file detection was confirmed by inspecting the git log commit messages and comparing against the known stable set of bin/ modules.
• Semgrep: not installed in this environment; the four CI Semgrep rules (SSRF, command injection, path traversal, _from_* bypass) were verified manually via grep equivalents.
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Generated by Claude Code