The verify pass submitted every extracted object, selected executables included,
on the stated grounds that "VirusTotal is content-addressed, so identical bytes
return the analysis it already holds instead of re-running 70+ engines".
That is measurably false. On v0.10.5 all EIGHT re-submissions produced a NEW
analysis - same VirusTotal file-id, timestamp 47 minutes later:
candidate: file-id=2c00f485... ts=1786795957 (12:12:37Z)
verify : file-id=2c00f485... ts=1786798758 (12:59:18Z)
Re-analysing identical bytes re-rolls a probabilistic classifier, and Microsoft's
ML engine answered differently within that hour, in BOTH directions:
82750cd1 (linux-amd64) microsoft-ml -> clean
6d3c5be6 (darwin-arm64) clean -> microsoft-ml
The published notes are generated from the candidate scan, so v0.10.5 shipped a
table calling linux-amd64 flagged when VirusTotal had it clean, and darwin-arm64
clean when VirusTotal was reporting Trojan:Script/Wacatac.B!ml. Every hash in
that table links to the page that contradicted it. Corrected in place after
publication; this removes the cause.
The second scan proved nothing the first did not. Identity is settled by hash
before this step runs: verify-release-selection.py reconciles every published
container to the selected bytes, and checksums.txt binds the same digests
publicly. A re-scan adds no assurance - only another roll.
What still gets scanned is exactly what the candidate pass never saw: install.sh,
install.ps1, LICENSE, THIRD_PARTY_NOTICES.md, the MCPB manifest.json and the
unpacked UI assets. install.sh and install.ps1 are the highest-consequence
non-executable bytes we publish - users pipe them straight into a shell - and
that coverage is untouched. Measured on the v0.10.5 object set: 16 objects in,
8 withheld, 8 still scanned.
The withheld set is recorded as evidence (cbm-virustotal-withheld-v1) naming each
sha256 and pointing at virustotal-candidate-results.tsv, so the published
evidence still accounts for every shipped object.
Fails closed three ways, each with an actionable message: no object matches a
selected sha (the containers do not carry the recorded bytes), everything is
withheld (the surface scan would be a no-op), or the selection names no shas at
all. The zero-match grep is wrapped rather than left to pipefail, because a
guard that aborts silently is not a guard - found by testing the guards rather
than assuming them.
Also drops 8 VirusTotal submissions per release.
Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>
Martin Vogel
bdb99d7750