Malicious PDF — malware analysis report

Static analysis result for SHA-256 f28d4bea0ee4a6d7…

MALICIOUS

PDF

85.3 KB Created: 2010-05-12 14:48:15 +08:00 Authoring application: WPS Office 个人版 (via PDFlib 7.0.0 (C++/Win32))
MD5: 387aaf0a3cc057502b1da36a35bfd3dc SHA-1: b0573d858ef55781fa97b4cb1f1187d9fb582087 SHA-256: f28d4bea0ee4a6d7a72b47745bdd6a739a65563527bb4d65fbd822e3775b322a
196 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution: Malicious File T1059.001 Command and Scripting Interpreter: PowerShell T1566.001 Phishing: Spearphishing Attachment

The PDF file contains embedded JavaScript that is obfuscated and utilizes the unescape() function, indicating malicious intent. The critical heuristic firing for CVE-2009-4324 confirms an exploit targeting a known vulnerability in Adobe Reader. The presence of a secondary embedded PDF further suggests a multi-stage attack. The JavaScript is likely responsible for downloading and executing a subsequent payload, a common technique for initial access.

Heuristics 7

  • media.newPlayer — CVE-2009-4324 critical CVE exact CVE_2009_4324
    PDF JavaScript calls media.newPlayer — CVE-2009-4324 is a use-after-free in Adobe Reader's multimedia plugin triggered by media.newPlayer(). Actively exploited as a zero-day in December 2009. (identified after JavaScript deobfuscation)
  • 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.
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
  • Suspicious extracted artifact medium 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.
  • 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 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 7

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_004_off0000063a.js
447cccb0b28690cfd35e6c7d285b83d1ca96a54fd0f2a437498ab8c6a303cc5d		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x63A 2610 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s). Carved artifact contains 1 long hex-escaped blob(s).
legacy_pdfkit_stage_000.js
42c3f4df375ff6f58ff655cc4f88b5cc28f0dd33b978390db3538684a6219b74		 deobfuscated-js string-concatenation normalized Acrobat API aliases at offset 0x63A 126 bytes
objstm_0023_00.bin
e8bfe65c34a535b0837ce7c541e45b42ab61e1ff13de05788daf7770f9a1ec0e		 pdf-objstm-decoded PDF /ObjStm 23 0 obj (inflated) 274 bytes
font_00_sfnt_off0000aa77.bin
bdab15c72ec5a37d61944db6415ea4ab85cd85c56ef86d8ba91cc069a9bc9da6		 pdf-font-stream PDF embedded font (sfnt) at offset 0xAA77 21464 bytes
font_01_sfnt_off0000ce2e.bin
6b1af86e742004cde4c431a20efa9af7f7ee7fd198a7188df96578bf3b0a3e79		 pdf-font-stream PDF embedded font (sfnt) at offset 0xCE2E 222716 bytes
polyglot_child_pdf_off00009fd3.pdf
be952edd29d6af2b8a0729f07fc8d9228de7c89b65adfdf520e61835c60daf06		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x9FD3 46432 bytes
polyglot_child_pdf_off00013d46.pdf
0b1c923c8a0028794f3a3244dc498786746334f394e41678cc58ffbeb707d0a8		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x13D46 6125 bytes

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