Malicious PDF — malware analysis report

Static analysis result for SHA-256 8d57ad88b76bc0de…

MALICIOUS

PDF

357.0 KB Created: 2010-02-22 08:19:16 +08:00
MD5: e91830cf36cd2e8daae768e4b563f48d SHA-1: 2c9be7da5bf531162fd401b8d157451207503f9a SHA-256: 8d57ad88b76bc0de5bbb02a8a125d1aeba1259c1051c0980a9ff6bdc9bbdd1c2
256 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and a Flash object (jVtTngBkmcyI.swf), indicated by multiple heuristic firings including PDF_JAVASCRIPT, PDF_JS, PDF_RICHMEDIA, and PDF_EVAL. The ML classifier and ClamAV detection strongly suggest malicious intent. The embedded JavaScript and Flash are likely used to exploit vulnerabilities within the PDF reader or to download and execute additional malicious content. The presence of extracted JavaScript files further supports this. The exact payload and delivery mechanism are not fully discernible from the provided evidence, hence the 'unknown family' classification.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 9

  • ClamAV: Pdf.Exploit.Agent-35955 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35955
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • RichMedia (Flash) high PDF_RICHMEDIA
    PDF contains /RichMedia (Adobe Flash) which is a historic exploit vector
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (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.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • 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/

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
jVtTngBkmcyI.swf
c2b666a3ef4c191b77b78c037656e50477b8ba3d35fd61ae843a3a1f4d41c5c1		 pdf-embedded-file PDF EmbeddedFile object 5 at offset 0x1518 26774 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35955
Obfuscation or payload: likely
Carved artifact entropy is 7.99, consistent with packed or encrypted content.
javascript_obj0012_000.js
a8e9a031915fc297bf10a6ec84576b5b55a9de0263ee4db0e5604573a17731a2		 pdf-javascript-stream PDF /JS object 12 at offset 0x3CD 9494 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
javascript_obj0028_001.js
70c940ca448d03dc56836c5dd011e2433261e89c9ce18ff31ddad7a53b4ae68c		 pdf-javascript-stream PDF /JS object 28 at offset 0x8CC3 18151 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).

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