Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c79784f0a8f344e…

MALICIOUS

PDF

118.6 KB
MD5: dab2617fcc26daf6a3ea0f7ffb879457 SHA-1: 71eba0f45dca667c78038dd6f769635ddd93d0a5 SHA-256: 4c79784f0a8f344e89bc6be71940de73711d183d8bfe2667edc6f3a0efe5595a
196 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

The PDF contains embedded JavaScript, including a large comment-padded eval stager, indicating an attempt to obfuscate malicious code execution. The ML classifier and ClamAV detection strongly suggest malicious intent. The primary attack vector appears to be JavaScript execution within the PDF, likely leading to the download and execution of a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 7

  • 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
67630063237f27c155f333d9450ecdd638acd0bfa9cfd810b0281df9355d1046
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627713 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).
legacy_pdfkit_stage_000.js
55db146def44092acd120db91829b38ef1b967e23e42f3e278a119abdd64023c
deobfuscated-js double percent-decoded annotation JavaScript at offset 0x143 262118 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 580 long base64-like blob(s).