test(proxy): fuzz the wire parsers + document the proxy as in-scope (HF Issue 1) - #90
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…ssue 1) The HF incident broke containment via a zero-day IN the sandbox's egress proxy — the component that parses attacker-influenced wire bytes from the agent it contains. Sandy's proxy is in the same position, so prove (not assume) its parsers are robust. - proxy/fuzz_test.go: FuzzExtractSNI / FuzzParseServerName / FuzzExtractHTTPHost with degenerate/truncated/oversized seed corpora. Invariant: never panic (a panic crashes the proxy = the agent's only egress route). 8s local fuzzing found no crashers (2M+ execs/target). - THREAT_MODEL §7: the proxy is documented as an in-scope tier-3 attack surface, not just a control. - Dependabot already covers proxy/go.mod (gomod, weekly) — no change needed. NOTE: the CI wiring (a 30s -fuzztime gate + advisory govulncheck in the proxy job) is NOT in this commit — pushing .github/workflows/ needs a workflow-scoped token, which this session's gh token lacks. The change is saved for a workflow-scoped push. The sandy-isolation-test 'attack the proxy' scenario is tracked in that repo. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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…ow-up) (#97) Completes HF-incident Issue 1: the proxy CI job now runs a short 30s -fuzztime pass per wire-parser fuzz target (FuzzExtractSNI/ParseServerName/ExtractHTTPHost, a HARD gate — any crasher fails the build) and govulncheck as ADVISORY (continue-on-error): stdlib patch latency is remediated by the proxy image's monthly golang-base refresh (Issue 3) + Dependabot on miekg/dns, so a new CVE surfaces without hard-breaking every unrelated proxy PR. Split from #90 because pushing .github/workflows/ needs a workflow-scoped token. Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
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HF-incident analysis Issue 1 (Medium — defence-in-depth on the highest-value component; LOW disclosure).
The incident's escape was a zero-day in the sandbox's egress proxy — the one component mandatory to trust, directly reachable by the contained agent, and parsing attacker-influenced wire bytes. Sandy's proxy is in that same position, so its parsers should be proven robust, not assumed.
proxy/fuzz_test.go:FuzzExtractSNI/FuzzParseServerName/FuzzExtractHTTPHostwith degenerate/truncated/oversized seed corpora. Invariant: never panic (a panic crashes the proxy process = the agent's only egress route). 8s local fuzzing per target found no crashers (2M+ execs each).proxy/go.mod(gomod, weekly) — the finding's dependency-advisory item is already in place.-fuzztimegate per target + an advisorygovulncheckstep in theproxyjob — is not in this PR because pushing.github/workflows/requires aworkflow-scoped token, which this session'sghtoken lacks. The exact change is ready to apply (see the maintainer note).govulncheckcurrently flags 21 stdlib vulns (toolchaingo1.24.1, fixed in ≥1.24.4) — which is precisely why it's advisory and why the proxy image now auto-refreshes its golang base monthly (Issue 3, #89).The
sandy-isolation-test'attack the proxy' scenario (malformed handshakes, oversized SNI, header smuggling, DNS abuse, connection exhaustion) is tracked in that separate repo.