Malicious PDF — malware analysis report

Static analysis result for SHA-256 ab1a56cb2e2a8208…

MALICIOUS

PDF

118.4 KB
MD5: 4e9c85c364840ac4a27f0c7f5903a72a SHA-1: eba6e3f89408eb3b4ad954b1a0e4496b78a726a6 SHA-256: ab1a56cb2e2a8208a6a8915a9bd12d6782b6b7e9a3f90c581d14483f67c2d965
166 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that utilizes eval() and String.fromCharCode(), indicating an attempt to obfuscate malicious code. High-confidence heuristics like 'PDF_EVAL' and 'PDF_JS_LARGE_COMMENT_PADDED_EVAL' strongly suggest the execution of a stager. ClamAV detection as 'Pdf.Exploit.Agent-36086' further confirms its malicious nature. The primary function appears to be downloading and executing a secondary payload, though the exact URL or payload is not directly extractable from the provided evidence.

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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0006_000.js
1eb254e0455833d957e63bf3682ff0e142e384ca6036e0da977d3720f66701c6
pdf-javascript-stream PDF /JS object 6 at offset 0x143 626086 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).