Malicious PDF — malware analysis report

Static analysis result for SHA-256 4d5ae3403a3420fc…

MALICIOUS

PDF

239.0 KB Created: 2010-06-11 11:09:09 +08:00 Authoring application: Acrobat PDFMaker 8.1 for Word (via Acrobat Distiller 8.1.0 (Windows))
MD5: 313345d9cb3be3de83937e086b141d05 SHA-1: 25030e7fda757ff38d33eb207fc58fe147bc7310 SHA-256: 4d5ae3403a3420fc9930bf5f8c48accc3f2ec6fcb6fad2391e00d7ede8715d40
258 Risk Score

Malware Insights

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

This PDF file was flagged as malicious by a machine learning classifier and ClamAV with the signature Pdf.Exploit.Agent-35955. It contains embedded JavaScript and a secondary PDF, indicating a multi-stage attack. The presence of RichMedia (Flash) and unescape() calls suggests an attempt to exploit vulnerabilities. The primary attack pattern involves luring the user into opening the PDF, which then likely executes embedded code to download and run a secondary payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9546

Heuristics 10

  • 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.
  • ClamAV: Pdf.Exploit.Agent-35955 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35955
  • 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)
  • 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://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/
    • http://www.aiim.org/pdfa/ns/id/

Extracted artifacts 8

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_002_off00000372.bin
25e2c64e83adbd7ffe184aaf2a08c702fdd3f20b21c4942fc3d4390881f7bd25		 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
icc_00_off0002211c.icc
2b3aa1645779a9e634744faf9b01e9102b0c9b88fd6deced7934df86b949af7e		 pdf-icc-profile PDF ICC profile at offset 0x2211C 3144 bytes
font_00_sfnt_off00028136.bin
352008e06901cf51c9d95baa8c1490c02f73e20490ae7db86db7818500050275		 pdf-font-stream PDF embedded font (sfnt) at offset 0x28136 146568 bytes
font_01_sfnt_off0002cd41.bin
a3e7720d516ea9ece7d1b1e16f4d20af866465ef36b66d28f0b7bf3f8f87ae47		 pdf-font-stream PDF embedded font (sfnt) at offset 0x2CD41 180200 bytes
font_02_sfnt_off00031401.bin
e4ba783b01ffa5ea5410a0a975a27b2a0bb6b9a4a8cb89001d7a28076eacc05a		 pdf-font-stream PDF embedded font (sfnt) at offset 0x31401 179776 bytes
polyglot_child_pdf_off0001f393.pdf
b32cd06f7b4316b8f47723f01509690207fb0bd99863dcef823f64c447a21e9a		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x1F393 116852 bytes
polyglot_child_pdf_off0003a41a.pdf
0b1c923c8a0028794f3a3244dc498786746334f394e41678cc58ffbeb707d0a8		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x3A41A 6125 bytes

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