Summary

The initial adversarial db.php state-machine campaign found four distinct hardening gaps in SqliteIntegrationProvider. The import-engine classification contract from #3993 passed across all 16 destination artifact combinations, including intentional-MySQL non-mutation.

Findings

• High: installSqliteIntegration() writes through an external wp-content/db.php symlink, modifying the symlink target outside the site and leaving the symlink in place.
• Medium: Any comment, string, or prefixed identifier containing SQLITE_DB_DROPIN_VERSION is treated as a compatible custom drop-in even though it does not define the constant. Generated variants reproduce this in both classification and installation.
• Medium: A file blocking wp-content/database/ causes installation to fail with EEXIST.
• Medium: A directory blocking wp-content/db.php causes installation to fail with EISDIR.

Reproduction

Candidate rig commit: df0b03d1f

git fetch origin fuzz/db-php-state-machine
git switch --detach df0b03d1f
node --experimental-strip-types scripts/fuzz-sqlite-dropin.ts

The deterministic seed is 3692. The runner executes 84 isolated filesystem cases and writes replay data, a JSONL case log, coverage summary, and campaign envelope under artifacts/db-dropin-fuzz/3692/.

Homeboy command:

homeboy fuzz run studio --path "$PWD" --workload component-script-1 \
  --tracker-ref "github-pr:Automattic/studio#3692" \
  --tracker-ref "github-issue:Automattic/studio#3518" \
  --seed 3692 --run-id studio-db-dropin-3692 \
  --gate-profile strict --require-case-log --require-coverage-summary \
  --require-result-envelope --isolation isolated --max-duration 2m

Initial evidence: homeboy://run/studio-db-dropin-3692. The strict run passed case-evidence, target-coverage, and operation-coverage gates; it failed only the expected zero-open-findings gate.

Coverage dimensions

• Destination SQLite artifact combinations
• Drop-in content spoofing
• Custom drop-in preservation
• Filesystem blocker recovery
• Symlink containment
• Intentional-MySQL non-mutation