Bernd RodlerandClaude Opus 4.8
f7e487171c
S-01 audited bulwarkmail/plugins/smime @ 91085a3 (2,935 lines). Nine findings, two HIGH. No backdoor and no exfiltration path anywhere in the bundle — the problems are trust-model and input-validation gaps. Full report in vnc/audits/SMIME-PLUGIN-AUDIT-2026-08-04.md. Fork is source-only. The upstream smime.zip is a 1.77 MB prebuilt bundle whose manifest reads 1.0.1 while the source reads 1.0.2, so auditing src/ would not audit what that zip installs. We build from source. Finding 1 (HIGH) — certificate substitution. maybeAutoImportSigner gated on signatureValid alone, but smimeVerify runs checkChain:false, so that only proves "signed by whoever holds this key", not that the claimed identity is real. Self-sign a cert asserting victim@example.com, send one signed message, and it was stored as the encryption target for that address — the user's next Encrypt to the victim went to the attacker. Now requires signerEmailMatch === true and !selfSigned. Both values were already computed and displayed as untrusted in the banner; only the import path ignored them. Tests for `true` explicitly so an undefined match (missing From header) fails closed. Finding 3 (MED-HIGH) — CRLF header injection. Escaping reached only Subject and attachment filename; display names, raw addresses, Message-ID, In-Reply-To, References and attachment Content-Type were emitted verbatim, and formatAddress escapes only backslash and quote. In-Reply-To/References/display names are copied from inbound mail when replying or forwarding, so the value is attacker-supplied. Sanitising inside formatHeader covers all 17 call sites by construction; the three headers assembled directly get stripCrlf explicitly. Also adds auth:observe to the manifest. The plugin registers onAfterLogout/onAccountSwitch — real hooks (lib/plugin-hooks.ts:362-363) — without declaring the permission, so under B-09 the session-key wipe would silently stop running. verify-fixes.mjs carries 19 assertions including source checks that fail if either guard is removed or a new unsanitised interpolated header appears. That last one immediately caught the interpolated smime-type Content-Type header, which manual review had dismissed as static. Finding 2 (unauthenticated CBC accepted on decrypt) is NOT fixed. This is not safe for real mail yet — sandbox accounts only. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
24 lines
1.8 KiB
XML
24 lines
1.8 KiB
XML
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1200 675" width="1200" height="675">
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<defs>
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<filter id="grain-smime-b" x="0" y="0" width="100%" height="100%">
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<feTurbulence type="fractalNoise" baseFrequency="0.85" numOctaves="2" seed="41" stitchTiles="stitch"/>
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<feColorMatrix values="0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0.16 0"/>
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<feComposite in2="SourceGraphic" operator="in"/>
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</filter>
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<linearGradient id="bg-smime-b" x1="0" y1="0" x2="1" y2="1">
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<stop offset="0" stop-color="#64748B"/>
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<stop offset="1" stop-color="#0F172A"/>
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</linearGradient>
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</defs>
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<rect width="1200" height="675" fill="url(#bg-smime-b)"/>
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<rect width="1200" height="675" fill="white" filter="url(#grain-smime-b)"/>
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<g transform="translate(120,200) scale(11.25)" fill="none" stroke="white" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round">
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<!-- lucide "shield-check" -->
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<path d="M20 13c0 5-3.5 7.5-7.66 8.95a1 1 0 0 1-.67-.01C7.5 20.5 4 18 4 13V6a1 1 0 0 1 1-1c2 0 4.5-1.2 6.24-2.72a1.17 1.17 0 0 1 1.52 0C14.51 3.81 17 5 19 5a1 1 0 0 1 1 1z"/>
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<path d="m9 12 2 2 4-4"/>
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</g>
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<text x="460" y="300" font-family="system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif" font-size="60" font-weight="700" fill="white" dominant-baseline="middle">S/MIME</text>
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<text x="460" y="360" font-family="system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif" font-size="24" font-weight="400" fill="white" fill-opacity="0.82" dominant-baseline="middle">Sign, encrypt, verify & decrypt mail</text>
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<text x="460" y="396" font-family="system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif" font-size="24" font-weight="400" fill="white" fill-opacity="0.82" dominant-baseline="middle">Your keys never leave the browser</text>
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</svg>
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