Malicious PDF — malware analysis report

Static analysis result for SHA-256 cbf2bdb2722923cb…

MALICIOUS

PDF

29.2 KB Created: 2013-02-04 13:49:43 Authoring application: BVueMyGp (via XWbt14Wq2SGq8) First seen: 2013-09-29
MD5: d68a1dbdc434ad743300fc99fb2697b7 SHA-1: 2c339e1268062f64deb350667212c710ee3d8ee0 SHA-256: cbf2bdb2722923cba0560d7a39bdba1127033ed321526239af6dc70ae9a90d49
72 Risk Score

Malware Insights

MITRE ATT&CK
T1555 Credentials from Password Stores T1027 Obfuscated Files or Information T1140 Deobfuscate/Decode Files or Information

The PDF was flagged as malicious by an ML classifier with high confidence. It contains an embedded file, which is a common technique for delivering malware. The presence of XFA forms and duplicate object bodies suggests obfuscation or attempts to evade detection. The embedded file itself is a strong indicator of a downloader or dropper.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9094

Heuristics 6

  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • 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://ns.adobe.com/xdp/ In PDF document text
    • http://www.xfa.org/schema/xci/1.0/In PDF document text
    • http://www.xfa.org/schema/xfa-template/2.2/In PDF document text
    • http://www.xfa.org/schema/xfa-data/1.0/In PDF document text
    • http://ns.adobe.com/xfdf/In PDF document text
    • http://www.xfa.org/schema/xfa-form/2.8/In PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0016.bin pdf-embedded-file PDF EmbeddedFile object 16 at offset 0x176A 28171 bytes
SHA-256: 3dc28ed4e4a4e43f36fd32d78703fa8a8b53f1fe53601b527f97ee60ffcee5cd
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
stream_018_off000056aa.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x56AA 120 bytes
SHA-256: 8028c643df4e264224bbf458f3d784a956b1606e3ec50ae4c1280f74a3ecec09

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