Malicious PDF — malware analysis report

Static analysis result for SHA-256 78d160c4c34490e7…

MALICIOUS

PDF

210.4 KB
MD5: fe157a4f01298f71706d38864376623e SHA-1: 50d360b6a80e5fe7f591de9597ab91fc6ce239f0 SHA-256: 78d160c4c34490e7f514b1ce5365d85d339e2bf44c1f3e7574398c105092e633
188 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF contains embedded JavaScript, with high-confidence firings for PDF_EVAL and PDF_UNESCAPE indicating obfuscated code execution. A secondary embedded PDF was also detected with similar suspicious findings. The ML classifier strongly flagged this PDF as malicious. The primary intent appears to be the execution of arbitrary JavaScript, likely to download and execute a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

Heuristics 7

  • Secondary embedded PDF body has suspicious static findings critical POLYGLOT_CHILD_PDF_STATIC_TRIAGE
    A valid PDF body was found at a nonzero offset inside another container and its carved contents matched PDF exploit or lure heuristics. This catches polyglots where the top-level magic routes to ZIP/OLE while a PDF reader or downstream parser opens the hidden PDF payload.
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
  • JavaScript action low PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/pdf/1.3/

Extracted artifacts 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0052_000.js
45fea71ee6347153ec3719ebc3910509cd6fa568f263c29e7474c694308f5c7d
pdf-javascript-stream PDF /JS object 52 at offset 0x3F4E 301 bytes
javascript_obj0059_001.js
28d6113dc29ef94de179a1345b6983a9d947da00c945e958d0554de4748a5164
pdf-javascript-stream PDF /JS object 59 at offset 0x6483 2612 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 3 long base64-like blob(s).
stream_005_off00000b74.bin
e4217c167299ac63f64b8b7e903cc0196f0828693d273431b8b793a12ed0fed3
decompressed-pdf-stream PDF FlateDecoded stream at offset 0xB74 1000 bytes
objstm_0053_00.bin
f9797d0fa28384c30d8bf1da89163104ce539753e417fa1f9c5fd135d1eceb39
pdf-objstm-decoded PDF /ObjStm 53 0 obj (inflated) 50 bytes
polyglot_child_pdf_off0002ddd2.pdf
fb2b52d852722f9b426665a5f60047fc463cd643a8f13b317d15efab7307f861
polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x2DDD2 27574 bytes