Malicious PDF — malware analysis report

Static analysis result for SHA-256 277ddb842c99330b…

MALICIOUS

PDF

185.2 KB
MD5: fc23b244194c9f5be2ac126d080eba32 SHA-1: 4975e031f197cd0221908fc8e73b8ce20539be70 SHA-256: 277ddb842c99330b78de3dd4c681506dddb7f782546e3349e92db1eb05f8e204
270 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File Execution: Malicious PDF T1059.001 Command and Scripting Interpreter: JavaScript

This PDF exploits CVE-2009-0658, a heap-spray vulnerability in Adobe Reader, using embedded JavaScript. The JavaScript is obfuscated and likely responsible for downloading and executing a second-stage payload. The presence of a secondary embedded PDF with similar suspicious findings further indicates a multi-stage attack. The primary exploit identified is CVE-2009-0658.

Machine Learning

  • Nyx PDF Classifier malicious score 0.6728

Heuristics 10

  • Adobe Reader JBIG2Decode heap-spray exploit critical CVE likely CVE_2009_0658
    PDF combines JBIG2Decode image streams with a Reader 9 JavaScript heap-spray stage. This is the in-the-wild Adobe Reader/Acrobat JBIG2Decode exploit shape associated with CVE-2009-0658.
  • JBIG2 + active content high CVE related PDF_JBIG2_ACTIVE_CONTENT
    JBIG2Decode appears with JavaScript/XFA/RichMedia — a related indicator for JBIG2 parser-exploit families including CVE-2021-30860 and CVE-2009-0658, but not a unique CVE fingerprint.
  • 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)
  • JBIG2Decode filter medium PDF_JBIG2
    JBIG2 image decoder present — historically used in zero-click exploits
  • 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)
  • 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 6

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_002_off00000310.js
a0c0de2e1bdb6b678dbe7cf719fb7d9b13ab2bc07f8552e835bea2054a38c5fd		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x310 1809 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s).
stream_005_off00002a45.bin
6a71966cad617bfb05c2fc57e09517130f7abf80fb7d2cd8d6f9a72dd0ff8cc6		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x2A45 8958 bytes
objstm_0029_00.bin
f8eb65864fd50b29cfa71dd142b8bbf6494c65d9fbb58bcb2b7b2c3ac3227298		 pdf-objstm-decoded PDF /ObjStm 29 0 obj (inflated) 88 bytes
jbig2_00_off000006b7.bin
05e62dd154e4c23a9ea6419bc55207b0ec9a101988fb14c2ca6b726751351011		 pdf-jbig2-stream PDF JBIG2 stream at offset 0x6B7 4945 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.93, consistent with packed or encrypted content.
jbig2_01_off00028cc3.bin
4fc5fd9bdd46c763dfaa373b14504131baf03f9314d69c0f1a6c1bf156c9676f		 pdf-jbig2-stream PDF JBIG2 stream at offset 0x28CC3 4945 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.96, consistent with packed or encrypted content.
polyglot_child_pdf_off0002860c.pdf
3302a99a86506e0bf6968dbafb05b5165d2c47783dd9b721b8272b33116045e1		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x2860C 24210 bytes

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