Malicious PDF — malware analysis report

Static analysis result for SHA-256 0c6a28c4f10ac65b…

MALICIOUS

PDF

118.7 KB
MD5: 635fa9b8f8c370982fcc2b75d69587df SHA-1: 95f652db925a4b9cfd0f2f534b24c413d0bb6fd1 SHA-256: 0c6a28c4f10ac65bccd8e6f4ca185d76c315082823eeecddb1c4b69b8a308d12
256 Risk Score

Malware Insights

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

This PDF file contains obfuscated JavaScript that utilizes eval() and String.fromCharCode, indicative of an exploit stager. The critical heuristic firings for PDF JavaScript exploit clusters and large comment-padded eval stagers strongly suggest it's designed to execute malicious code. The ClamAV detection of 'Pdf.Exploit.Agent-36086' further confirms its malicious nature, likely serving as a downloader for further stages.

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
47169a0b8198a497b9051bcfac9ebc42318bb63002c97c7662209b852d478121
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627295 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_off0001d766.bin
5f719d1e85c3eb51665fe679240d26abbb9ba5f191143e903c0d09efbd6a2ac1
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1D766 300 bytes