Malicious PDF — malware analysis report

Static analysis result for SHA-256 a2d389106e84b8cc…

MALICIOUS

PDF

7.8 KB
MD5: d3913a9f41a7cc10a78b88d2c6318d6d SHA-1: 656ef201b294489c0abeaa11ad27a7d25a9691c1 SHA-256: a2d389106e84b8cc6526846ec136dbdc5466096eb0031e18f422b0fcf6b537d0
224 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.001 Malicious Link T1071.001 Web Protocols T1204 User Execution

The file is a malicious PDF exploiting CVE-2007-5659. It contains heavily obfuscated JavaScript that is designed to download and execute a second-stage payload. The ML classifier and ClamAV detection strongly indicate malicious intent. The primary attack vector involves exploiting a PDF vulnerability to run arbitrary code.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 8

  • Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659
    PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (identified after JavaScript deobfuscation)
  • ClamAV: Pdf.Exploit.Agent-35916 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35916
  • Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER
    PDF JavaScript shows 5 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_codec_loop, hex_dashed_payload, incremental_eval_build, repeated_pluginschk. This is strongly consistent with pre-2011 Adobe Reader PDF droppers — OpenAction JS reads encoded data from annotation subjects, decodes it through one or more hex / base-N loops, and invokes eval indirectly (method name built one character at a time). The actual CVE is hidden in the final decoded layer and is not visible via static analysis.
  • 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.
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules. (matched inside decoded stream)
  • syncAnnotScan annotation-staging primitive low PDF_FOXIT_SYNCANNOTSCAN
    PDF JavaScript calls syncAnnotScan() — a no-op annotation-enumeration primitive used by exploit-kit JavaScript to stage payload reads from annotation /Subject fields before eval(). Not a vulnerable sink itself; rarely seen in legitimate PDFs. (matched in decompressed stream)
  • 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.

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0005_000.js
6c41320119e160dc719997b9a2efb3600ea9d7e9d7e44b4dc2125762dc9f365f
pdf-javascript-stream PDF /JS object 5 at offset 0x148 505 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
legacy_pdfkit_stage_000.js
47b3e5251e2f1fb733a80db921fe63ec147b1efaad21649a26f958e4347ef34a
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1A22 1775 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
ca083432272983b75de1f8d4bd92983efd8ec89ab8e41d64aa55f4c3f57f8e22
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x355 4916 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
deobfuscated.js
0c82fc541fd5ec9fb9bff2f4ee1e5816974286dacad2b6030c5e7865468d9afd
deobfuscated-js PDF JavaScript deobfuscation pass 26976 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 7 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).