IOC Federation¶

An IOC (Indicator of Compromise) list is a versioned inventory of known-bad artifacts: confirmed-malicious domains, file hashes, and package names. It sits outside the heuristic score. When a PKGBUILD matches an IOC entry, TrustSight emits a definitive, attributed finding ("this source domain is on emiliano-go's known-bad list, incident atomic-arch-2026-06") with no score, no band, and no probability language. This is detection, not inference.

The design rests on four principles:

• State, not rules. IOCs are observations about the world, so they live in the baseline layer next to the corpus baseline (A13/A13b), never in the rule config. An override or a weight cannot reach them.
• Attribution, not aggregation. Every match names the curator that flagged the artifact. The user sees who called it bad, and can follow the incident and evidence.
• Federation, not centralization. Independent curators publish signed baselines; TrustSight verifies, imports, and reports with source labels.
• Expiration, not permanence. IOCs carry a time-to-live. An expired indicator is reported as expired, never silently ignored and never permanently flagged.

The baseline format¶

A baseline is a directory:

ioc-baseline/
├── manifest.json
└── iocs.jsonl

manifest.json¶

{
  "version": 1,
  "source": "emiliano-go",
  "created_at": "2026-08-09T00:00:00Z",
  "expires_at": "",
  "signature": "<hex ed25519 signature, or empty>",
  "public_key": "<hex ed25519 public key, or empty>"
}

iocs.jsonl¶

One JSON object per line:

{"type": "domain", "value": "evil-cdn.xyz", "source": "emiliano-go", "confidence": "high", "provenance": "ASA-2026-06", "campaign": "atomic-arch-2026-06", "expires_at": "2026-09-15T00:00:00Z"}
{"type": "hash", "value": "deadbeef...", "source": "emiliano-go", "confidence": "high", "provenance": "vendor report"}
{"type": "package", "value": "malicious-aur-pkg", "source": "emiliano-go", "provenance": "ASA-2026-06"}

Any entry with an unknown type, an unusable value, or no source is dropped with a warning; the rest import.

Indicator types and normalization¶

Signature¶

signature is a detached Ed25519 signature over the canonical manifest.json (with the signature field emptied) concatenated with iocs.jsonl byte-for-byte. Verification uses the public_key in the manifest. An unsigned baseline imports only with --allow-unsigned, which is for a baseline you built and trust locally.

How matching works¶

A dedicated IOC Match stage runs after rule matching and before scoring:

Parse -> Tokenize -> Rule Match -> IOC Match -> Score -> Verdict

It reads the diff's added lines (or the whole PKGBUILD text when available) and queries the stored indicators for every source-URL host, every checksum and hex digest, and the package/pkgbase/dependency names. Hits are attached to PackageFact.ioc_matches; see the report schema.

Each IocMatch carries type, value, source, confidence, provenance, campaign, the surface it was found on (source_host, checksum_array, package_name, a dependency field, ...), the line, and expired.

What an IOC match does not do¶

• It never changes the score. Matches live on ioc_matches, never in score_breakdown; the same PKGBUILD scores identically with or without a hit. IOCs are attribution the reviewer can verify, not a number.
• It is not downgraded by a coverage gap, positive evidence, or an override. If an indicator matched in the analysed text, it is reported.
• It does not disappear when it expires. An expired indicator is still reported, labelled expired, so a lapsed indicator never reads as clean. Only trustsight ioc list hides expired entries by default (pass --include-expired).

These properties are enforced by the gates an IOC match carries its source, IOC matches never contribute to the score, an expired IOC is never silent, and IOCs are not in the rule config layer (see the enforcement map).

Configuration and commands¶

The [baselines.ioc] section and its feeds are documented in configuration. The trustsight ioc {sources,import,update,list,export} commands are documented in the CLI reference.

Storage is the ioc_entries table, keyed by (type, value, source). Importing a baseline for a source replaces that source's rows and leaves other sources (and expired rows) untouched, so imports are idempotent and attributable.

Harvesting¶

Turning advisories and community reports into signed baselines is the job of a separate project, not TrustSight's codebase: a harvester proposes candidate entries, human curators review and sign, and TrustSight only ever consumes the signed output. Keeping the harvester out of the tool is what keeps the IOC gate non-evadable by construction: a hash either matches or it does not, and no code in TrustSight decides what belongs on the list.