Malicious PDF — malware analysis report

Static analysis result for SHA-256 5a97fde2ff4befd6…

MALICIOUS

PDF

85.1 KB Created: 2010-03-30 20:31:14 +08:00
MD5: 466c93287fba6e148db4f358289fafd3 SHA-1: 8c63da4705f3eb58c13ed48474dedd9d448555da SHA-256: 5a97fde2ff4befd645b80e6a31fa8df3d7549af79a8385ef3aca0303fbe77a51
158 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF sample contains embedded JavaScript, indicated by multiple PDF_JAVASCRIPT and PDF_JS heuristics. The presence of PDF_JS_EXPLOIT_CLUSTER and PDF_EVAL firings strongly suggests the JavaScript is malicious and intended to exploit a vulnerability for code execution. The embedded JavaScript stream, named 'stream_002_off00000375.js', is the primary artifact of interest, likely serving as a downloader or initial execution vector for further malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.6619

Heuristics 7

  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
  • 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. (matched inside decoded stream)
  • 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. (matched inside decoded stream)
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload (matched inside decoded stream)
  • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_002_off00000375.js
d09b3f8531bbd0b9fb1a15b94dac709f7710e3e969ad94204049ce689fed2ee0		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x375 18155 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
objstm_0042_00.bin
e324194cd048d339510dbb2e905b3d4dd544e3e66457eb38e6957ef9fcb256ab		 pdf-objstm-decoded PDF /ObjStm 42 0 obj (inflated) 3331 bytes

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