Malicious PDF — malware analysis report

Static analysis result for SHA-256 841c4e95f1f27ce0…

MALICIOUS

PDF

239.3 KB Created: 2010-06-11 11:09:09 +08:00 Authoring application: Writer (via OpenOffice.org 3.0)
MD5: b8746a9b4c80b9b73ecc632cdfb8c5e3 SHA-1: d4cbec8beb4ece7aee8da6f0d9a7675517541597 SHA-256: 841c4e95f1f27ce02e8015fbfc1ef566a3cd50007b76c52405257418e7411e27
166 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript and a secondary embedded PDF, indicated by multiple PDF-related heuristic firings. The presence of 'unescape()' calls and RichMedia (Flash) suggests an attempt to obfuscate or execute malicious code. The polyglot nature and embedded streams point towards a multi-stage attack, likely for delivering a secondary payload or exploiting a vulnerability. No specific family could be identified due to the generic nature of the findings.

Heuristics 8

  • 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.
  • RichMedia (Flash) high PDF_RICHMEDIA
    PDF contains /RichMedia (Adobe Flash) which is a historic exploit vector (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. (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 8

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_002_off00000372.bin
9cfc3705daa053d177a459f9e6bc46101919540f22572f901c01c8bbaba870fe		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x372 3386 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
objstm_0015_00.bin
cbd11d2ce487f41cb2e696adc35306d2f3d38b7de6eab25b0e0d07f05d693f12		 pdf-objstm-decoded PDF /ObjStm 15 0 obj (inflated) 912 bytes
font_00_sfnt_off0001bea1.bin
2744adb4ebaea4f8f108c9109ab8935fc059c24e9812985fb7afd06d7e9b1186		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1BEA1 48648 bytes
font_01_sfnt_off00023830.bin
4bfb851f15c1f0cbd12e2903acdda7af933bd94a51a8ee6bbe36a84f81d61039		 pdf-font-stream PDF embedded font (sfnt) at offset 0x23830 104600 bytes
font_02_sfnt_off0003200a.bin
2c8de1c863fed688e55fe27e93f226a7886f1a045de634cecb69bdd6d387f0d9		 pdf-font-stream PDF embedded font (sfnt) at offset 0x3200A 41744 bytes
font_03_sfnt_off0003669f.bin
cfd8475624654acefe85dfed82dabe01906f123e364aa1043e26d7815b7265f5		 pdf-font-stream PDF embedded font (sfnt) at offset 0x3669F 37416 bytes
polyglot_child_pdf_off00017bb3.pdf
d911fef81914c96f9669238056da78c1bb62b5016114617b4ea9c26d653e6c0a		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x17BB3 147852 bytes
polyglot_child_pdf_off0003a552.pdf
0b1c923c8a0028794f3a3244dc498786746334f394e41678cc58ffbeb707d0a8		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x3A552 6125 bytes

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