Malicious PDF — malware analysis report

Static analysis result for SHA-256 9cd8aa0cb0123406…

MALICIOUS

PDF

138.3 KB Created: 2011-04-25 22:48:14 +08:00 Authoring application: Writer (via OpenOffice.org 3.0)
MD5: d8dd59b6bb9a4e5b44732bc69995d9d0 SHA-1: 9f677c7011a1a2c6e84263c8510b73e2946583e4 SHA-256: 9cd8aa0cb0123406fa9c3d5b3347eb03dceaf459ea045e62cc81326ad3ce5ee6
140 Risk Score

Malware Insights

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

The PDF file was flagged as malicious by an ML classifier and contains embedded rich media, specifically a Flash object. Further analysis revealed a secondary embedded PDF with suspicious static findings, indicating a multi-stage attack. The presence of embedded PDFs suggests an attempt to obfuscate or deliver a secondary malicious payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9571

Heuristics 5

  • 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)
  • 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)
  • 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.
  • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objstm_0026_00.bin
a857974669b840d75523cf076c96d626e5e0fa5284200c320ba77d68058c256a		 pdf-objstm-decoded PDF /ObjStm 26 0 obj (inflated) 1061 bytes
polyglot_child_pdf_off00014167.pdf
3eca27d9eb3e87dd58df41ab88d3cec4c0ea19c11b6446bf16c88f729fdc6f06		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x14167 59363 bytes
polyglot_child_pdf_off0002115d.pdf
0b1c923c8a0028794f3a3244dc498786746334f394e41678cc58ffbeb707d0a8		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x2115D 6125 bytes

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