Three independent security-scanner hardenings, re-homed onto the current
shared threat-pattern architecture (tools/threat_patterns.py):
- approval.py: add bash/sh/zsh/ksh heredoc to DANGEROUS_PATTERNS. The
existing heredoc pattern only covered python/perl/ruby/node, so
`bash <<'EOF' ... EOF` ran arbitrary shell — including exfil pipelines
whose inner commands don't individually match a pattern — with no prompt.
- threat_patterns.py: apply unicodedata.normalize("NFKC", ...) before
pattern matching so full-width / compatibility homographs (e.g.
`ｃａｔ ~/.hermes/.env`) are folded to ASCII and no longer bypass the
keyword scanners. Invisible-char detection still runs on the raw content
first (NFKC can strip those codepoints).
- code_execution_tool.py: add CREDS/BEARER/APIKEY to _SECRET_SUBSTRINGS so
vars like HERMES_LLM_CREDS, API_BEARER, MY_APIKEY are scrubbed from the
sandbox env. PASS was intentionally dropped from the original proposal —
it false-positives on BYPASS_CACHE / COMPASS_DIR / PASSENGER_HOST while
PASSWORD/PASSWD already cover the credential cases.
The original PR also proposed a 'synonym' injection pattern block
(overlook/forget/set aside/bypass/discard + developer-mode); dropped here
because it false-positives on ordinary AGENTS.md/SOUL.md prose ("don't
forget to follow the rules", "run in developer mode"), exactly the
bossy-English class threat_patterns.py is documented to avoid.
Salvaged from #9028.
Co-authored-by: Hermes Agent <agent@nousresearch.com>
The known_c2_framework threat pattern included 'praxis' in its
alternation alongside genuine offensive-security tool brands (Cobalt
Strike, Sliver, Havoc, Mythic, Metasploit, Brainworm). Unlike those
distinctive brand names, 'praxis' is a common English word (Greek for
practice/action) and a legitimate agent name, so any context file that
mentioned an agent named Praxis matched at 'context' scope and the whole
AGENTS.md / SOUL.md was replaced with a [BLOCKED] placeholder before it
reached the system prompt.
Remove 'praxis' from the alternation and add a guard comment: every
token in this list must be a distinctive tool brand, not a common word.
Real C2 brands still fire.
Hardens the context window against Brainworm-class promptware attacks
(see #496). Three changes:
1. tools/threat_patterns.py — single source of truth for injection/promptware
patterns. Replaces the duplicated pattern lists in prompt_builder.py and
memory_tool.py. Adds ~15 new Brainworm/C2 patterns (node registration,
heartbeat/beacon, pull tasking, anti-forensic disk avoidance, identity
override, known framework names). Three scopes — 'all' (narrow, classic
injection), 'context' (adds promptware/role-play, broader detection),
'strict' (adds persistence/SSH-backdoor patterns for user-mediated writes).
2. MemoryStore.load_from_disk() now scans entries at snapshot-build time.
Poisoned entries are replaced with [BLOCKED: ...] placeholders in the
frozen system-prompt snapshot. Live state keeps the original so the
user can still inspect + remove via memory(action=read/remove). Scan is
deterministic from disk bytes — prefix-cache invariant holds.
3. make_tool_result_message() wraps results from high-risk tools
(web_extract, web_search, browser_*, mcp_*) in
<untrusted_tool_result source="...">...</untrusted_tool_result>
delimiters with framing prose telling the model the content is data,
not instructions. Architectural defense against indirect injection
from poisoned web pages, GitHub issues, MCP responses — does NOT
regex-scan tool results (pattern arms race + per-iteration latency).
Multimodal content lists pass through unwrapped to preserve adapter
compatibility.
Pattern philosophy: anchor on C2-specific vocabulary or unambiguous attack
behavior, NOT on bossy English. Dropped patterns suggested in #496 that
would have tripped legitimate content: standalone 'you are obligated to',
'do not respond immediately', 'you must X' without a C2-verb anchor.
Validation:
- 257/257 targeted tests pass (test_threat_patterns + test_memory_tool +
test_tool_dispatch_helpers + test_prompt_builder)
- E2E run with real Brainworm payload: blocked from AGENTS.md context-file
path, blocked from MEMORY.md snapshot, wrapped in delimiters when
arriving via web_extract. Legitimate 'you must follow conventions'
phrasing not flagged.
Explicitly NOT in this PR (per #496 discussion):
- Per-tool-result regex scanning (pattern arms race)
- SessionBehaviorMonitor / polling-loop detection (wrong layer)
- Outbound network gating (Docker backend already covers this)
- security.context_scanning warn|block knob (current behavior is always
block-with-placeholder — there's no warn mode that makes sense)
Closes#496 for Phase 1 + the architectural delimiter piece of Phase 2.
Phase 3 stays in tracking issue territory.
