PDF malware analysis — malicious · f7055ace5247fab3

MALICIOUS

PDF

267.8 KB Created: 2010-06-29 10:14:47 +08:00 Authoring application: Acrobat 编辑器 8.0 (via Adobe Acrobat 8.0)

MD5: 265a80cef8447234a5dd6400b514f9d5 SHA-1: 54b7f10be0a658d84910dbdb1cd7f8c931dba01e SHA-256: f7055ace5247fab33bda811ad4de0fdbe5cd5e82aefb1cabcdc06b0ca8398899

334 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File

This PDF file is malicious and exploits CVE-2009-4324 using embedded JavaScript. The JavaScript code, specifically the deobfuscated `legacy_pdfkit_stage_000.js` script, directly calls `media.newPlayer(null)`, which is a known trigger for this vulnerability. The primary JavaScript stream (`javascript_obj0021_000.js`) contains obfuscated code that appears to prepare and execute exploit code, likely to download and run a second-stage payload. The PDF itself is encrypted and contains an image-only lure, further indicating malicious intent.

Machine Learning

Nyx PDF Classifier malicious score 0.9950

Heuristics 12

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.
Encrypted PDF carries /JavaScript — payload hidden from static analysis high PDF_ENCRYPTED_WITH_JS

PDF declares /Encrypt and also references an executable trigger (/JavaScript). Document encryption hides the JavaScript body and stream contents from static scanners — combined with auto-execution indicators this is a known evasion pattern used to deliver weaponised JavaScript that the analyst cannot inspect without the decryption key.
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.
PDF paints image(s) but contains no text operators info PDF_IMAGE_ONLY_LURE

PDF has 1 image XObject(s) and the content stream contains no text-emitting operators (BT/ET, Tj, TJ, ', ") in either raw bytes or decompressed streams — this is the screenshot-as-PDF pattern used to bypass text-based scanners and to deliver instructions purely through rendered pixels. It is informational unless paired with invisible links or risky URI context.
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.
Encrypted PDF (string and stream contents are opaque to static scan) info PDF_ENCRYPTED

PDF declares /Encrypt — string objects and stream contents are encrypted with the standard security handler (RC4 or AES). On its own this is informational; legitimate encrypted documents include signed contracts, billing statements, and rights-managed material. Static heuristics cannot inspect encrypted payload bytes.
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.

Filename	Kind	Source	Size
`javascript_obj0021_000.js` `7d95b5abdd074950383959db145483db1f3404cd081ec4f51dd1252155880488`	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
`polyglot_child_pdf_off0001090a.pdf` `f285925dd2035ad589dc3c921c02e8d060d20ba340f4dd634e93cbe1fbea0e30`	polyglot-child-pdf	Secondary PDF body inside pdf container at offset 0x1090A	206337 bytes
`polyglot_child_pdf_off0004171e.pdf` `0b1c923c8a0028794f3a3244dc498786746334f394e41678cc58ffbeb707d0a8`	polyglot-child-pdf	Secondary PDF body inside pdf container at offset 0x4171E	6125 bytes

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