Malicious PDF — malware analysis report

Static analysis result for SHA-256 a6e76643943fa7b5…

MALICIOUS

PDF

173.9 KB Authoring application: Acrobat PDFMaker 7.0 for Word (via Acrobat Distiller 7.0 (Windows)) First seen: 2015-10-04
MD5: cab8cf6f5d83c54df271749ee296a65f SHA-1: 92c58c28f974f2cac7796e385efae3042cd70709 SHA-256: a6e76643943fa7b5b66e11486384db9709808b96002ca15ef8a6871d619bf66e
112 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF file was flagged as malicious by an ML classifier with high confidence. It contains embedded JavaScript, indicated by the 'PDF_JAVASCRIPT' and 'PDF_JS' heuristics, and a suspicious extracted artifact named 'stream_004_off00029b92.js'. The presence of JavaScript suggests an attempt to download and execute a secondary payload, which is a common attack vector for malicious PDFs. The document body was truncated and unreadable, preventing further analysis of its lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 6

  • JavaScript action low 2 related findings PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Obfuscated multi-stage PDF JavaScript heap-spray exploit critical CVE related PDF_JS_OBFUSCATED_MULTISTAGE_HEAPSPRAY
    PDF JavaScript hidden behind nested stream filters and/or a custom in-JS decoder (rolling-XOR stager) decodes to a heap-spray / ROP chain. The spray is only visible after unwinding those layers, which is why the raw heap-spray rules miss it. This is an obfuscated multi-stage Adobe Reader JavaScript exploit; the dropped Windows payload (often named Win.Trojan.Agent by signature AV) is the second stage, not the delivery mechanism.
  • 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.
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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# In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/pdfx/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/photoshop/1.0/In PDF document text

Related samples 2

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_004_off00029b92.js decompressed-pdf-stream PDF FlateDecoded stream at offset 0x29B92 5131 bytes
SHA-256: 5734d867bf4c9e7f8b731eb657fb526dc59d4246a18a08ddd9cc4d42db3034fb
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).

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