Malicious PDF — malware analysis report

Static analysis result for SHA-256 78a4dba7b224466e…

MALICIOUS

PDF

534.5 KB
MD5: c9df306089c1b735c2b66682713fa7f2 SHA-1: f243a3716a7ac0265c2be5dcdd2637fabfe8d9ee SHA-256: 78a4dba7b224466efe9f8a647b96627600452a3576db5d3296da46755d891477
312 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript T1566.001 Spearphishing Attachment

The sample is a PDF file that contains embedded JavaScript. Heuristics indicate the JavaScript is obfuscated and exploits CVE-2009-4324 (media.newPlayer). The JavaScript is designed to download and execute a second-stage payload, as evidenced by the generic stage recovery findings and the embedded polyglot PDF. The benign URLs found are likely decoys or standard PDF namespaces.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9969

Heuristics 10

  • 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. (matched in decompressed stream)
  • 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)
  • Generic recovered JavaScript exploit stage high PDF_GENERIC_STAGE_RECOVERY
    Bounded static stage recovery exposed hidden JavaScript through generic transforms such as null-byte collapse, percent decoding, marker replacement, arithmetic character codes, fromCharCode, numeric arrays, numeric-array minus-key decoders, alphabet-index arrays, /Producer half-difference metadata arrays, hex literals, marker-stripped Base64 literals, custom 6-bit XOR table decoders, or repeated-marker hex carriers. This rule is emitted only when the recovered stage contains exploit-like Acrobat JavaScript or shellcode markers.
  • 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.
  • 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/

Extracted artifacts 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0057_000.js
582d7232c85854b6fafb996019d8b5fd223c4b72b0395dcba206f3174be781a3		 pdf-javascript-stream PDF /JS object 57 at offset 0x551F 2186 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
stream_005_off00000b74.bin
e4217c167299ac63f64b8b7e903cc0196f0828693d273431b8b793a12ed0fed3		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0xB74 1000 bytes
generic_stage_recovery_000.js
51a89d769482a190889d1b511f84c7fe1ed3c7636666bb61f16f4d7048e64e0e		 deobfuscated-js generic stage recovery marker-XX-to-%u from JavaScript object 57 at offset 0x551F 1695 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
objstm_0053_00.bin
f9797d0fa28384c30d8bf1da89163104ce539753e417fa1f9c5fd135d1eceb39		 pdf-objstm-decoded PDF /ObjStm 53 0 obj (inflated) 50 bytes
polyglot_child_pdf_off0007ee5f.pdf
8690527bfd597cbde9d1feea0f4efdab6b44a5885209ce19603d3dbe257d3bd8		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x7EE5F 27598 bytes

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