rea/docs/pe-certificates.md

PE Authenticode certificate tables

inspect_pe_certificates / inspect-pe-certificates answers whether one selected local PE32/PE32+ image declares an IMAGE_DIRECTORY_ENTRY_SECURITY table, which WIN_CERTIFICATE entries that table stores, and which PKCS#7 signer and X.509 fields those entries carry. It reads the file without executing it and does not require a Windows SDK, catalog file, or disassembler.

rea inspect-pe-certificates /absolute/path/to/application.exe --json

The CLI resolves relative paths against the caller's working directory. MCP and the advertised input schema require an absolute filesystem path and preserve that exact selection:

{
  "name": "inspect_pe_certificates",
  "arguments": { "path": "/artifacts/application.exe" }
}

Observations

The inline Evidence result contains the artifact path, SHA-256, and byte length. table is the file-offset security directory, or null when the directory is absent or zero. Each entries[] item reports WIN_CERTIFICATE length, revision, type, and the payload SHA-256.

Type-2 entries may count their zero alignment padding in dwLength. The PE entry owner accepts only the exact gap to the next eight-byte boundary after the parsed ContentInfo; extra data or nonzero counted padding fails. Entry ranges retain all declared bytes, including counted padding. CMS payload ranges and hashes exclude counted padding.

For WIN_CERTIFICATE type 2 (PKCS#7 signedData) pkcs7 contains digest algorithm OIDs, embedded X.509 serial/issuer/subject/validity fields, and signer identifier facts. A signer identified by subject key identifier reports that value as subject_key_identifier_hex. Other certificate types keep pkcs7 null.

Each signer reports unsigned_attribute_oids: null means the field was absent, and an array lists the types when present. Older retained Evidence may omit the field. Unsigned attribute contents, including nested signatures and timestamp tokens, are not decoded; their presence makes coverage partial and adds a limitation. Certificate and signer counts refer to the outer SignedData.

A missing table is observed absence of that directory. It is not proof the image is unsigned in every catalog or overlay sense.

Limits and failures

The selected file is limited to 64 MiB by default (512 MiB maximum). At most eight WIN_CERTIFICATE entries are examined by default. Malformed PE headers, truncated certificate entries, and PKCS#7 that is not structurally signedData fail without partial success. A security directory that ends in fewer than eight header bytes, including zeros, is a truncated WIN_CERTIFICATE and fails the same way. SignedData must contain at least one SignerInfo, and each SignerInfo must carry a non-empty signature value. Each embedded X.509 certificate must include subjectPublicKeyInfo and signatureValue. Decoded certificate name text, serials, validity spellings, and subject key identifiers share a 64 KiB budget per PKCS#7 payload, and each payload decodes at most 16,384 ASN.1 values. Exhausting either fixed allowance returns a nonretryable resource_constraint error naming it, not an invalid-input error; this release has no runtime override, and max_file_bytes and max_entries do not raise it. Unsupported certificate name encodings, including GeneralString, fail explicitly. TeletexString (T.61) values are rendered with the ISO-8859-1 compatibility mapping used by OpenSSL; this is not a full T.61 decoder, so the result includes a limitation whenever that mapping is used. RFC 5280 retains TeletexString for backward compatibility and describes its repertoire as ASCII-like Latin with additional characters.

The structural CMS reader accepts definite lengths and BER indefinite lengths for constructed values, including the outer ContentInfo sequence. Primitive values must have definite lengths. Embedded X.509 certificates and signed attributes must also use definite length encoding, as required by their DER profiles. This is a bounded structural subset: it does not implement every BER string form or validate DER canonical encoding, and it does not verify signatures.

This workflow does not verify signatures, certificate chains, timestamps, or Authenticode digest coverage of image bytes.