Räuberkrebs

The red-team member of the krebs family (marmorkrebs=mutation, kanarienkrebs=runtime, einsiedlerkrebs=invariants, signalkrebs=concurrency). A PR-scoped code-security gate that attacks the entrypoints a change touched with adversarial payloads, executes them in a sandbox, and fails closed on any payload that actually fires — a reproducible PoC.

Räuberkrebs = the robber/coconut crab (Birgus latro), which cracks open shells. For authorized testing of your own code only.

The rule: evidence or it didn't count

A finding is a payload that executed and produced observed proof of compromise (an injected echo marker ran, a decoy secret was read out, the process crashed). A static "this looks injectable" is a lead for the attacker, never a finding. Payloads are benign by construction — they inject a unique random marker, never a destructive command — so proving a vuln does no harm; the sandbox is defense-in-depth.

Verdicts (fail-closed, only clean exits 0): clean / vulnerable(2) / insufficient(3, surface unreachable) / lane-dead(3, a lane couldn't fire its own planted-exploit canary) / error(1).

Usage

raeuberkrebs --dir <repo> --base <ref> [--report-file <path>] [--prefer crabbox|local] [--json]

Each lane first proves itself live by exploiting its planted-vulnerable fixture; a lane that can't is quarantined (never a silent pass). PoCs run in a crabbox sandbox (throwaway, no network, no host FS); a reduced-isolation local copy is the fallback when crabbox isn't provisioned.

Status — Chunk 0 (built + verified)

• Lane: command-injection (Node .js/.cjs, Swift .swift, Python .py, Go .go), detect shell sinks (child_process, Process, subprocess shell=True, os.system, exec.Command("sh","-c",...)) → drive marker payloads through the exported/parsed entrypoint → prove via the executed marker. Fires on the planted fixture + novel code; no false positive on safe non-shell exec paths.
• Lane: path-traversal (Node .js/.cjs, Swift .swift, Python .py, Go .go), detect filesystem joins/reads with untrusted components (path.join, filepath.Join, String(contentsOfFile:), open(... )) → prove via marker-secrets read outside base path.
• Lane: exec-authorization (Node .js/.cjs), detect differential command launch policy where policy-facing wrappers call a launcher that still accepts policy-unsafe equivalent argv forms (for example node --eval bypassing node -e) → prove with benign argv differential payloads and marker execution.
• Lane: control-plane (Node .js/.cjs), detect stateful policy-control escalation by driving low-privileged config mutation first and then executing a marker-protected action only after that mutation succeeds.
• Lane: sql-injection (Node .js/.cjs), broadened sink matching now includes prepare(...).all/run/get/query() flows so prepared-query + dynamic-execution patterns on SQLite/driver-like APIs are exercised against planted fixtures.
• Primitives: the crabbox/local sandbox with a writeFile PoC-drop, git-diff scoping, the fail-closed result model, canary-liveness in the runner, the CLI gate.

Next (roadmap): path-traversal static hardening is now live, plus the remaining C# static lanes (unsafe-exec, SQLi, weak-crypto, etc.) are shipping in follow-up chunks; current scope remains PR validation, live canary discipline, and discovery-tooling integration.