Malicious PDF — malware analysis report

Static analysis result for SHA-256 b8ab99dc6735ebdd…

MALICIOUS

PDF

151.2 KB Created: 2010-06-29 10:14:47 +08:00 Authoring application: Acrobat 编辑器 8.0 (via Adobe Acrobat 8.0)
MD5: 9119d07c03642a3d88734659ec19c03e SHA-1: f06115c498daaa34d6c51b45c4ca9a201b0eb846 SHA-256: b8ab99dc6735ebdddaaf146348cbcd9dbe952ceb77bc8d22a0cc57d826a5b80f
290 Risk Score

Malware Insights

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

This PDF file contains embedded JavaScript that exploits CVE-2009-4324 via the media.newPlayer API. The script is heavily obfuscated but appears to be designed to download and execute a second-stage payload. The presence of multiple PDF JavaScript exploit cluster heuristics and the ML classifier's high confidence score indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9995

Heuristics 9

  • 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)
  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
  • 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.
  • 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.
  • 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 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0021_000.js
142d5fc8ede06be4c352cd93615d4c93a6b4a1c1377bf84183b6675d2ae5e6f7		 pdf-javascript-stream PDF /JS object 21 at offset 0x514 2119 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 2 long base64-like blob(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 0x514 126 bytes
font_00_sfnt_off0001ea41.bin
ae1403fb25d4ff480c18964b60f29dbf0fbf1953caebc9554c608041bde9c953		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1EA41 106240 bytes
polyglot_child_pdf_off0001db02.pdf
f6cbec031dc1a6c5ca77d907bee3c184c58c10bcc5e38c5de83bb4e83cf67376		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x1DB02 33212 bytes
polyglot_child_pdf_off000244d1.pdf
0b1c923c8a0028794f3a3244dc498786746334f394e41678cc58ffbeb707d0a8		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x244D1 6125 bytes

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