Malicious PDF — malware analysis report

Static analysis result for SHA-256 091a11fb21a05c2d…

MALICIOUS

PDF

118.8 KB
MD5: e2b64b8c003a03ef82046689ef671a1d SHA-1: 9810be55bafe6e0779e077c752471ca08411f080 SHA-256: 091a11fb21a05c2d8ab0cb385fe07c80276b4b7c4cf084910c408012e49faaad
256 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution

This PDF sample contains obfuscated JavaScript that utilizes eval() and String.fromCharCode() functions, indicative of an exploit. The critical heuristic 'PDF_JS_EXPLOIT_CLUSTER' and ClamAV detection 'Pdf.Exploit.Agent-36086' strongly suggest it's designed to exploit a PDF vulnerability. The embedded JavaScript is likely responsible for downloading and executing a secondary malicious payload.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 8

  • 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.
  • ClamAV: Pdf.Exploit.Agent-36086 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36086
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • Large comment-padded JavaScript eval stager high PDF_JS_LARGE_COMMENT_PADDED_EVAL
    PDF JavaScript contains a very large stream padded with long random-looking block comments around String.fromCharCode and eval. This is an exploit-kit obfuscation shape used to bury a decoder and recovered stage inside noise, not normal PDF form automation.
  • 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)
  • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0006_000.js
406f32762f7fde62ed0df7877b070967eb8cf332caccd4fe9d663c8d40c0a186
pdf-javascript-stream PDF /JS object 6 at offset 0x143 628024 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 42 long base64-like blob(s).
stream_001_off0001d799.bin
fe2e6b657065ca8039f545fb3eb60c5fcb633ce17c8f2f58d27953d05eace369
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1D799 300 bytes