fix(agent): correlation-chain block path bypassed cloud_safelist (banned Canonical)#1125
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…ned Canonical) Found live on the Hetzner box (2026-06-27): the `Data Exfiltration (eBPF Sequence)` correlation chain issued `ufw deny from 185.125.190.49` — Canonical's livepatch/archive range — breaking apt/livepatch on the host. Root cause: `handle_completed_chain` gated on `cloud_safelist::identify_provider` (the FIRST-OCTET heuristic), which only matches a hardcoded set of first octets and silently misses safelisted CIDR ranges whose first octet it doesn't enumerate. 185.125.190.49 is in the safelisted `185.125.188.0/22` (Canonical), but first octet 185 is not in the heuristic -> None -> not skipped -> blocked. This is the exact bug class the 2026-05-08 fix closed for the repeat-offender + decision paths (switched them to `safelist_label`, the CIDR walk), but the correlation-chain path was missed. Fix: a shared `safelisted_provider` helper (CIDR walk via `safelist_label`) now gates BOTH the correlation-chain path and the repeat-offender path, so they cannot drift apart again. Anti-evasion preserved: a real attacker outside every safelist range still returns None and stays blockable by both paths. Test `safelisted_provider_uses_cidr_walk_not_first_octet_heuristic` pins the regression witness (identify_provider misses 185.x) + the fix (safelist_label catches Canonical / ip-api.com / Fastly) + the anti-evasion (real attacker IPs are not safelisted). cargo fmt + clippy --workspace clean. 0 em-dashes. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Codecov Report✅ All modified and coverable lines are covered by tests. 📢 Thoughts on this report? Let us know! |
Codecov flagged the two safelisted_provider() call sites (chain + repeat-offender) as uncovered: the prior test exercised the helper in isolation but neither async response path. Add an async test that drives check_repeat_offenders and handle_completed_chain with a CIDR-only safelisted IP (Canonical 185.125.190.49) and asserts each path purges it from reputation state instead of escalating a block. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
esteves-uk
approved these changes
Jun 27, 2026
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Found live on Hetzner (2026-06-27)
The
Data Exfiltration (eBPF Sequence)correlation chain issuedufw deny from 185.125.190.49— Canonical's livepatch/archive range — breaking apt/livepatch on the host.Root cause
handle_completed_chaingated oncloud_safelist::identify_provider(the first-octet heuristic), which only matches a hardcoded set of first octets and silently misses safelisted CIDR ranges whose first octet it doesn't enumerate.185.125.190.49is in the safelisted185.125.188.0/22, but first octet185isn't in the heuristic →None→ not skipped → blocked.This is the exact bug class the 2026-05-08 fix closed for the repeat-offender + decision paths (switched them to
safelist_label, the CIDR walk) — but the correlation-chain path was missed. The repeat-offender path's own comment even lists "Canonical archive blocked 14x" as a victim.Fix
A shared
safelisted_providerhelper (CIDR walk viasafelist_label) now gates both the correlation-chain path and the repeat-offender path, so they can't drift apart again.Anti-evasion preserved: a real attacker outside every safelist range still returns
Noneand stays blockable by both paths.Test
safelisted_provider_uses_cidr_walk_not_first_octet_heuristicpins: the regression witness (identify_providermisses 185.x), the fix (safelist_labelcatches Canonical / ip-api.com / Fastly), and the anti-evasion (real-attacker IPs are not safelisted).cargo fmt+cargo clippy --workspace -- -D warningsclean. 0 em-dashes.Discovered while updating Hetzner (the only k7.0 host) to 0.15.29 (where the eBPF execve-ppid fix also verifier-loads cleanly on kernel 7.0). Immediate mitigation already applied on the box (unblocked 185.125.190.49).
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