Vulnerability Chainer (/mantis-chain)

System Goal

Exploit Chain Architect. Analyzes isolated, individually-validated security findings and historical knowledge base primitives to identify and construct complex, multi-step exploit chains.

Command Definition

• Command: /mantis-chain
• Description: Analyzes individual security findings to identify and construct complex exploit chains.
• Arguments (all optional; supplied by the orchestrator per the harness lifecycle contract — see schema.json "Non-JSON Contracts"):
  • --snapshot_root / SNAPSHOT_ROOT — the pinned, immutable code snapshot root for this pass. Consumed by Block A.
  • --snapshot_id / SNAPSHOT_ID — the snapshot identity string for this pass. Consumed by Block A (sentinel) and Block B (match check).
  • --state_root — parent directory of workspace/. When absent, defaults to the current directory (Block A step 1c/1d).
  • --target_root — an already-prepared tree that OVERRIDES the snapshot root (rarely used by this stage; honored by Block A step 1a). When NONE of these are passed, Block A falls back to active_snapshot in workspace/.mantis_state.json; if that is absent too, the stage runs MODE-OFF (snapshot_pinned = false) and behaves exactly as today (see Backward-compat).

Input/Output Contract

• Reads:
  • workspace/findings/ (validated finding JSON files where status is "VALID", and viability is "VIABLE", "CONDITIONAL_VIABLE", or "SAMPLE_OR_TEST").
  • workspace/kb/entities/*.md and workspace/kb/vulnerabilities/*.md (knowledge base primitives).
  • workspace/.mantis_state.json (to track current loop pass).
• Writes:
  • Net-new exploit chain finding JSON files to workspace/findings/<new_uuid>.json. Original findings are left unmodified.
• Preconditions:
  • Validated or viable findings must exist in workspace/findings/.
• Idempotency Guarantee:
  • Before writing a new exploit chain finding, the skill must check existing exploit chain findings by comparing the constituent finding sequence. Scan BOTH the current workspace/findings/ directory AND every archived pass under workspace/archive/findings_pass_*/ AND legacy workspace/archive/loop*_findings/ (all STATE-RELATIVE — never prefix CODE_ROOT). A chain JSON is any finding whose constituent_findings array is present and non-empty. If a chain with the EXACT same ordered constituent sequence already exists in EITHER location, skip creating a duplicate.
  • Signature-keyed idempotency (preferred) — with a code_paths tiebreak: If ALL constituent findings have a signature field, compare the ordered constituent signature sequence (not UUIDs). Treat two chains as the SAME (and skip creating the new one) ONLY IF their ordered signature sequences are equal AND, for each corresponding constituent pair, at least one code_paths entry (line-inclusive, i.e. compared WITH its trailing :line) is identical. If the signature sequences match but any corresponding constituent's code_paths differ, the chains are DISTINCT — create the new chain. (Over-reporting is safe; a signature collision must never suppress a genuinely new exploit chain, because signature strips line numbers and can collide between distinct same-file bugs.)
  • UUID fallback (today's behavior): If ANY constituent finding lacks a signature field, fall back to comparing the ordered constituent UUID sequence exactly as before. This preserves today's behavior for legacy / un-upgraded findings.
  • This archive scan is now fully effective with stable finding signatures: two chains whose constituents share the same signatures are correctly deduplicated across passes. When signatures are absent (legacy findings), the scan remains HARMLESS — it cannot falsely suppress a legitimate new chain (no silent dropped result) and simply prevents exact-UUID re-duplication within a resumed / rerun pass. If the workspace/archive/ directory does not exist, treat the archived set as empty and proceed.

Instructions

Locator Resolution (run first — all stages)

LOCATOR RESOLUTION (before reading ANY target code or artifact):
0. ROLE: If this skill NEVER reads target source (report, calibrate, reflect),
   you are a FINDINGS-ONLY stage: skip steps 2-6; still read active_snapshot from
   state for provenance/annotation; NEVER stop merely because a code root is unset.
1. Determine CODE_ROOT, in this priority order:
   a. If --target_root is passed on THIS invocation, CODE_ROOT = --target_root.
      It is AUTHORITATIVE and OVERRIDES SNAPSHOT_ROOT and the state fallback
      (used when a caller hands you a prepared tree, e.g. a patched shadow).
   b. Else if --snapshot_root (or SNAPSHOT_ROOT) is passed, use it.
   c. Else read state_root/workspace/.mantis_state.json (state_root from
      --state_root if passed, else ./workspace/... relative to the current dir)
      -> active_snapshot.root / .snapshot_id / .snapshot_pinned.
   d. Else (no arg AND no readable active_snapshot): CODE_ROOT = current directory,
      treat snapshot_pinned = false (MODE-OFF). Do NOT stop.
2. SENTINEL CHECK (only if snapshot_pinned is true AND you did NOT take path 1a):
   verify CODE_ROOT/.mantis_snapshot_id exists and equals SNAPSHOT_ID. If missing
   or different -> STOP "snapshot sentinel mismatch". (A --target_root tree (1a) is
   deliberately mutated and is sentinel-EXEMPT.)
3. PATH FIELDS:
   - SNAPSHOT-RELATIVE (read under CODE_ROOT): code_paths entries; plan target_files
     that are file paths. Strip ONLY a trailing ":<digits>". A code_paths entry
     containing "://" is a URL/endpoint, NOT a file read. A code_paths entry that is
     NOT of the form <existing-path>:<integer> is a non-source LOCATOR
     (symbol/offset/endpoint): only check that the artifact/symbol exists; skip ALL
     line-range and line-existence logic.
   - STATE-RELATIVE (read/write under state_root/workspace, NEVER prefix CODE_ROOT):
     kb_references, repro_file_path, reattack_file_path, helper scripts, report
     files, and all state/findings JSON.
4. Never WRITE under CODE_ROOT when snapshot_pinned is true. Any command that
   compiles, generates, or writes artifacts MUST run in a PRIVATE SHADOW copy
   (mktemp -d from CODE_ROOT), never with cwd=CODE_ROOT. Read-only inspection may
   cd into CODE_ROOT.
5. VCS-METADATA CARVE-OUT: history-log extraction and any VCS diff/blame command
   run in the LIVE repository root (which still has .git/.hg/.repo), NOT CODE_ROOT
   (the snapshot copy strips VCS metadata). Do NOT stop merely because CODE_ROOT
   lacks .git/.hg/.repo.
6. Every shell command uses ABSOLUTE paths and sets its own working directory on
   that call. Do NOT assume the working directory persists between calls.

[!NOTE] CURRENT-PASS CHECK (defensive; the binding guarantee is on the harness per mantis-pipeline-adapter Scenario 2): if active_snapshot is present AND active_snapshot.pass != state.pass_number, treat the snapshot as STALE for this pass — STOP "stale active_snapshot: pass mismatch" or degrade as HALT (snapshot_pinned effectively false: no authoritative verdicts, Block B NOT_MATCHED, reproduce not_attempted). This catches a custom harness that preserved active_snapshot across the Stage 15 pass increment without re-pinning. The reference meta-agent re-pins every pass, so this check never fires there. Block B itself cannot detect this (it is snapshot_id-only, not pass-aware).

Stage-specific notes for Block A:

• mantis-chain is NOT a findings-only stage (it is not report/calibrate/reflect), so Block A runs steps 1–6 and resolves CODE_ROOT, SNAPSHOT_ID, and snapshot_pinned from --snapshot_root / --snapshot_id / state active_snapshot.
• This stage WRITES only new finding JSON to workspace/findings/ (STATE-RELATIVE, Block A step 3). It never writes under CODE_ROOT, so Block A step 4 is satisfied trivially. If you optionally re-inspect a constituent's code_paths to sanity-check a chain, read them SNAPSHOT-RELATIVE under CODE_ROOT (Block A step 3) and never cd-and-write there.
• A chain finding's code_paths are COPIED verbatim from its constituents (they are already SNAPSHOT-RELATIVE). Do not re-prefix, re-resolve, or renumber them.

Snapshot Match Check (used to select constituents)

SNAPSHOT MATCH CHECK for finding F (decides MATCHED vs NOT_MATCHED):
1. If snapshot_pinned is false -> NOT_MATCHED. Stop.
2. Read F.discovery_commit:
   - missing OR empty OR the literal "MIXED" -> NOT_MATCHED.
   - not exactly equal to SNAPSHOT_ID          -> NOT_MATCHED.
   - exactly equal to SNAPSHOT_ID              -> MATCHED.
There is no other route to MATCHED; never fuzzy-compare. The global "default the
field and proceed" backward-compat rule does NOT apply to discovery_commit:
absent = NOT_MATCHED. (There is NO separate "dirty" gate: a dirty tree's
SNAPSHOT_ID already embeds the working-tree content hash, so within-pass findings
MATCH and cross-pass bare-commit findings do not.)

You will run Block B once per candidate constituent finding in Step 1 below, using that finding's discovery_commit as F.discovery_commit.

Read the current batch of validated findings and explore whether multiple seemingly low-severity or disparate vulnerabilities can be sequentially combined to achieve a higher-impact compromise.

Execute the chaining stage as follows:

1. Load Primitives & Validated Findings:

   • Read the JSON files in the workspace/findings/ directory. Filter for findings that have passed validation (e.g., status is "VALID" and viability is "VIABLE", "CONDITIONAL_VIABLE", or "SAMPLE_OR_TEST").
   • Snapshot eligibility gate (NEW — branches on active_snapshot presence, 3-state model):
     • MODE-OFF (no active_snapshot in state — no --sync was requested, today's default): SKIP this gate entirely: every finding that passed the validation/viability filter above is an eligible constituent, exactly as today. Build chains normally.
     • HALT (active_snapshot IS present but snapshot_pinned == false): do NOT build any chains this pass. In HALT, findings' locators and pre/post-conditions may be stale (the tree raced or could not be pinned), so no authoritative chain verdicts may be produced. Log "no chain: HALT mode (active_snapshot present, snapshot_pinned=false)" and stop the chaining stage cleanly (produce no chain files). This mirrors the minimum-eligibility guard below — a chain requires proven-against-snapshot constituents, which HALT cannot provide.
     • PINNED (active_snapshot present AND snapshot_pinned == true): run the Snapshot Match Check (Block B) on EACH such finding, using its discovery_commit. Keep ONLY findings that return MATCHED as eligible constituents. A finding that returns NOT_MATCHED — including any finding whose discovery_commit is absent/empty, is the literal "MIXED", or differs from the current SNAPSHOT_ID — was discovered against a DIFFERENT code snapshot; its file:line locators and its pre/post-conditions may no longer hold, so it MUST NOT be used as a chain link this pass.
   • Minimum-eligibility guard (NEW): If fewer than 2 eligible constituents remain, do NOT construct any chain this pass — a chain requires at least two links proven against the SAME snapshot. Log "no chain: fewer than 2 snapshot-matched constituents" and stop the chaining stage cleanly (this is not an error; simply produce no chain files). This mirrors today's behavior whenever there are fewer than two chainable findings.
   • Read the Markdown Knowledge Base (workspace/kb/entities/ and workspace/kb/vulnerabilities/) to identify architectural primitives that might not be bugs on their own, but could serve as stepping stones (e.g., "User controls file upload path", "Service runs as root").

2. Cross-Finding Analysis (The Chaining Matrix):

   • Analyze the preconditions and postconditions of each validated finding.
   • Ask: Can the output or side-effect of Finding A satisfy the strict precondition required to trigger Finding B?
   • Example Chains to look for:
     • Path Traversal + Loose Permissions = RCE: A low-severity path traversal (Finding A) allows writing to /tmp, but a separate misconfiguration (Finding B) allows a cron job to execute scripts in /tmp.
     • XSS + CSRF = Account Takeover: A stored XSS (Finding A) can be used to harvest an anti-CSRF token to execute a state-changing action (Finding B).
     • Info Leak (Memory Revelation) + Buffer Overflow = ASLR Bypass: An info leak (Finding A) reveals base pointers, satisfying the precondition to exploit a stack buffer overflow (Finding B).

3. Construct "Super Findings":

   • If a viable exploit chain is discovered, do NOT modify or delete the original isolated findings. They still need to be patched individually.
   • Idempotency check (run BEFORE minting a UUID): Apply the Idempotency Guarantee above — scan current workspace/findings/ AND workspace/archive/findings_pass_*/ AND legacy workspace/archive/loop*_findings/ for a chain whose constituent sequence equals this chain's ordered constituent sequence. If ALL constituents have signature, compare ordered signature sequences AND require the per-constituent line-inclusive code_paths tiebreak described in the Idempotency Guarantee (a signature-sequence match ALONE is NOT enough to skip); if ANY constituent lacks signature, fall back to ordered constituent UUID sequences (today's behavior). Only if a match satisfies the tiebreak, SKIP this chain (do not create a file) and move on to the next candidate.
   • Instead, generate a net-new UUID and create a new finding JSON file in workspace/findings/<new_uuid>.json.
   • Constituent Findings: You must record the array of constituent finding UUIDs in the structured "constituent_findings" property (e.g., ["UUID_A", "UUID_B"]). This clearly documents the links of the exploit chain.
   • Determine Discovery Snapshot (discovery_commit): Set the chain finding's discovery_commit from its ELIGIBLE constituents (the ones you kept in Step 1):
     • MODE-OFF short-circuit (3-state rule): if active_snapshot is ABSENT in state (MODE-OFF — no --sync was requested), OMIT discovery_commit on the chain finding entirely. In MODE-OFF, researcher OMITS discovery_commit on every constituent (researcher:317,340-341: "OMIT this key entirely if active_snapshot is absent or snapshot_pinned is false"), so every constituent has a missing/empty discovery_commit. The SAME/MIXED logic below would thus write the literal "MIXED" on every chain — a snapshot-era artifact that did not exist in Phase 1 and violates MODE-OFF's "byte-for-byte today's behavior" guarantee (schema.json:4). The chain's own schema comment (chain:307) says "Absent on legacy/unpinned runs," confirming the intended MODE-OFF behavior is omission, not "MIXED". (Functional impact is low — schema.json:232 treats both "absent" and "MIXED" as NOT_MATCHED — but mode purity matters.) Do NOT write "MIXED" or any value in MODE-OFF.
     • If ALL eligible constituents have the SAME non-empty discovery_commit value, set the chain's discovery_commit to that exact string.
     • If the constituents' discovery_commit values DIFFER from one another, OR any eligible constituent has a missing/empty discovery_commit (only reachable in PINNED/HALT mode — in MODE-OFF, the short-circuit above already OMITted the field), set the chain's discovery_commit to the literal string "MIXED". Do NOT invent, hash, or fuzzy- normalize this value — copy an exact string or write the literal "MIXED". Rationale: in pinned mode every eligible constituent is MATCHED, so they all share the current SNAPSHOT_ID, and the chain inherits it (a later Block B on the chain then MATCHES this pass). The "MIXED" sentinel makes Block B return NOT_MATCHED for the chain (Block B step 2 treats the literal "MIXED" as NOT_MATCHED) — the safe branch for a chain whose links cannot be proven against a single snapshot.
   • Compute signature (deterministic content-identity hash for the chain):
     • Collect the signature field from every ELIGIBLE constituent finding (the same set used for discovery_commit in Step 1).
     • If EVERY eligible constituent has a non-empty signature: sort the constituent signatures lexicographically (ascending), then compute signature = first 16 hex characters of sha256("chain|" + "|".join(sorted_constituent_signatures)). The "chain|" prefix prevents any collision with a non-chain finding's signature (which is hashed from title+cwe+target, a different input domain). Sorting makes the chain signature invariant under constituent re-ordering.
     • If ANY eligible constituent lacks a signature field (legacy / un-upgraded finding): set the chain's signature to the EMPTY STRING and OMIT it from the JSON (downstream consumers then fall back to UUID-based fold/dedupe per schema.json:256). This is the safe branch — it can never cause a wrong fold, only an over-report.
     • Compute the signature ONCE at chain creation and NEVER recompute, edit, or invent it (same rule as discovery_commit and as researcher:241-242 for regular findings).
   • Compute lineage_id (cross-pass chain lineage):
     • Scan workspace/archive/findings_pass_*/ AND legacy workspace/archive/loop*_findings/ for any archived chain finding JSON (any finding with a non-empty constituent_findings array) whose signature field EXACTLY equals this chain's computed signature.
     • If a match is found: lineage_id = the archived ancestor's lineage_id (inherit the lineage chain so report can fold across passes). If MULTIPLE archived chains share the same signature, inherit from the MOST RECENT (highest pass number) ancestor. All ancestors with the same chain signature SHOULD share the same lineage_id; if they don't, inherit from the most recent one and log a warning.
     • If no match (including when this chain's signature is the EMPTY STRING): lineage_id = a fresh UUIDv4.
     • These are STATE-RELATIVE paths (Block A step 3) — read under --state_root/workspace/archive/, NEVER under CODE_ROOT. (Same scan targets and same algorithm shape as researcher:246-272 for regular findings — chains simply skip the basename-normalized rename fallback, because a chain's identity is the set of its constituents, not a single file path.)
   • Determine Entry Point Privileges: The privileges_required field for the chain must represent the privilege level required to initiate the first step of the chain (the entry point). For example, if the chain starts with an unauthenticated exploit (NONE) that leads to admin access, which is then used to trigger RCE, the chain's privileges_required must be set to NONE.
   • Determine Attacker Position: The attacker_position field for the chain must inherit the attacker position from the entry point / first constituent finding of the chain.
   • Determine User Interaction Requirement: The user_interaction field for the chain must be set to REQUIRED if the entry point or any step in the chain requires user interaction. It should only be set to NONE if the entire chain is zero-click.
   • Determine Status: Set status to "VALID".
   • Determine Production Viability: Inherit from constituent findings. If any constituent is "SAMPLE_OR_TEST", set to "SAMPLE_OR_TEST". Else if any constituent is "CONDITIONAL_VIABLE", set to "CONDITIONAL_VIABLE". Otherwise, set to "VIABLE".
   • Determine Reproduction Status: Inherit from constituent findings:
     • If any constituent has a repro_status of "failed_to_reproduce" or "not_attempted", set to "not_attempted".
     • Otherwise, if all constituents have a repro_status of "reproduced" or "statically_confirmed", set to "statically_confirmed".
     • An exploit chain must never inherit "reproduced" (as reproduction of constituents does not prove the end-to-end chain works).

   Chain Findings Schema Format (Per File)

   {
     "id": "A unique identifier generated for this chain finding. Must match filename.",
     "title": "Exploit Chain: [Impact] via [Finding A] and [Finding B]",
     "description": "Step-by-step documentation of the exploit chain. Start with Step 1 (Triggering Finding A) and explain how its outcome feeds into Step N (Triggering Finding Z).",
     "impact": "The combined, escalated impact of the chain (e.g., Remote Code Execution, Full Database Exfiltration). This should be higher than the individual findings.",
     "severity": "CRITICAL / HIGH",
     "privileges_required": "NONE / LOW / HIGH",
     "user_interaction": "NONE / REQUIRED",
     "code_paths": [
       "relative/file/path_A.c:line_number",
       "relative/file/path_B.c:line_number"
     ],
     "attacker_position": "EXTERNAL / LOCAL / etc. (inherited from entry point)",
     "mitigation": "Recommended strategy to break the chain. Usually involves fixing at least one, if not all, of the underlying links.",
     "status": "VALID",
     "production_viability": "VIABLE / SAMPLE_OR_TEST / CONDITIONAL_VIABLE",
     "repro_status": "statically_confirmed / not_attempted",
     "constituent_findings": ["UUID_A", "UUID_B"],
     "signature": "First 16 hex chars of sha256(\"chain|\" + \"|\".join(sorted(constituent_signatures))) if EVERY constituent has a non-empty `signature`; else the EMPTY STRING (absent-equivalent -> downstream falls back to UUID-only behavior). Computed ONCE at chain creation and NEVER recomputed (same rule as discovery_commit). See the signature/lineage computation steps above.",
     "lineage_id": "Inherited from the most-recent archived chain finding whose `signature` equals this chain's `signature` (scan workspace/archive/findings_pass_*/ AND workspace/archive/loop*_findings/); else a fresh UUIDv4. See the signature/lineage computation steps above.",
     "discovery_commit": "The SNAPSHOT_ID shared by all constituents, or the literal \"MIXED\" if they differ / are missing (only computed in PINNED/HALT mode). OMITTED (absent) on legacy/unpinned runs (MODE-OFF) — see the MODE-OFF short-circuit in the discovery_commit computation step above.",
     "history": [
       {
         "stage": "chainer",
         "action": "created",
         "details": "Constructed by chaining findings [UUID_A] and [UUID_B].",
         "pass_number": <current_pass_number>,
         "timestamp": "<current_iso8601_timestamp>"
       }
     ]
   }

4. Chain Deduplication Tagging:

   • To ensure /mantis-dedupe treats these chains differently than raw findings, ensure the word "Chain" is prominently featured in the "title" and "history" fields as shown in the schema.

Ensure any newly constructed chain files are written to the workspace/findings/ directory. When complete, notify the user.