PDF_SIGNATURE_POST_SIGN_MODIFICATION — PDF modified after it was signed

high PDF_SIGNATURE_POST_SIGN_MODIFICATION

What it means

Bytes were appended after the signed/certified byte range.

Why it fires

An incremental update was appended AFTER a signature's ByteRange. Bare appends are normal (re-signing, form-fill), so this is only raised when the appended region introduces active content (/OpenAction, /JavaScript, /Launch, a new /Catalog, …) — the documented PDF 'shadow attack', where the viewer still shows the original signature as valid while rendering/executing content the signer never approved — or when a DocMDP no-changes certification is violated.

Other PDF heuristics

PDF_LAUNCH_JS_PROTOCOL PDF_LAUNCH_COMMAND PDF_LAUNCH_MSHTA PDF_ADOBE_QR_UNLOCK_LURE PDF_JS_URL_KEYED_READER_EXPLOIT_KIT CVE_2009_2990_U3D_AUTOACTIVATE PDF_ANNOT_AUTHOR_EVAL_STAGER PDF_ANNOT_SUBJECT_HEX_EVAL_STAGER PDF_ANNOT_SUBJECT_MARKER_EVAL_STAGER PDF_JS_BASE_N_TOKEN_DOWNLOADER PDF_BASE64_PE_PAYLOAD PDF_BRAND_INVOICE_LURE_OFFDOMAIN PDF_BRAND_INVOICE_CLOUD_EMAIL_LURE PDF_CORPORATE_PRESENTATION_CLOUD_REDIRECT_LURE PDF_CORRUPTED_FILE_UPDATE_LURE PDF_CRACKED_SOFTWARE_SHORTLINK_LURE PDF_GAME_HACK_SEO_LINK_FARM PDF_DISTRIBUTED_PIRACY_LINK_FARM PDF_DOCUSIGN_DOWNLOAD_LURE PDF_DOCUMENT_ACTION_HOST_MISMATCH_LURE PDF_DYNAMIC_DNS_DOCUMENT_LINK_FARM PDF_SWF_NATIVE_MEMORY_CORRUPTION_PAYLOAD PDF_EMBEDDED_PE_PAYLOAD CVE_2010_1240_EMBEDDED_EXPORT_LAUNCH