Malicious PDF — malware analysis report

Static analysis result for SHA-256 49299d2435260300…

MALICIOUS

PDF

401.9 KB Created: 2011-04-18 15:20:20 +08:00 Authoring application: Microsoft® Office Word 2007
MD5: f090075095cb2b01103e435b4342fba5 SHA-1: 5b0969af084e09bf921b98733cf70c731122235b SHA-256: 49299d24352603004691e4d32ad946eaed9f06cb267e5f50f78fd3e557221bb7
180 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious File T1059 Command and Scripting Interpreter T1059.001 PowerShell T1059.003 Windows Command Shell

The sample is a PDF file that exhibits multiple high-severity heuristic firings, including indications of embedded malicious content and a relation to CVE-2023-26369. The ML classifier also flagged it with high confidence. The presence of embedded files and rich media (Flash) suggests an attempt to deliver a secondary payload or exploit. While no specific script content was provided for analysis, the PDF structure and heuristic findings strongly indicate an exploit attempt targeting PDF viewers.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9663

Heuristics 6

  • TrueType bitmap font + active content — CVE-2023-26369 related high CVE related PDF_CVE_2023_26369_RELATED
    PDF embeds a TrueType font with bitmap tables (EBDT/sbix/CBDT) alongside exploit delivery indicators — CVE-2023-26369 exploits the sfac_GetSbitBitmap function in Adobe's libCoolType for arbitrary code execution. This CVE was actively exploited in the wild, but this rule does not validate the malformed EBLC/EBDT primitive.
  • 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_013_off0001fe1c.bin
f027ac9dfeb0f6d526988e6f2f7e74db2697e5c5a6ea11895814cd1495e5f93a		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1FE1C 120104 bytes
objstm_0026_00.bin
0841ed6ca2149b386133777ff3868f6222ba5033d6f52cd654a117610818bd40		 pdf-objstm-decoded PDF /ObjStm 26 0 obj (inflated) 1084 bytes
polyglot_child_pdf_off0001eb29.pdf
fa2d4d1b9a224870bbcd14874b6b78fbf7820b1759474f6454820deaa2075fc2		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x1EB29 285821 bytes
polyglot_child_pdf_off00062fb9.pdf
0b1c923c8a0028794f3a3244dc498786746334f394e41678cc58ffbeb707d0a8		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x62FB9 6125 bytes

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