Malicious PDF — malware analysis report

Static analysis result for SHA-256 3718d6032d98349c…

MALICIOUS

PDF

118.6 KB
MD5: 8137c2e09a0c58267e139b284bbcb951 SHA-1: be6f22ab922a9a79348cf5b6d5d024b17db884cf SHA-256: 3718d6032d98349c48c3e7cc4b88bc74e853a7b8857d8eefdad61c265b088fe5
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. Heuristics suggest this JavaScript acts as a stager, likely downloading and executing a second-stage payload. ClamAV detection confirms this as a known exploit, specifically 'Pdf.Exploit.Agent-36086'. The attack pattern involves exploiting PDF vulnerabilities to achieve arbitrary code execution.

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
1da599253135a8cfb3eb3a64a927826a4b70d3c4873ebe7ca4666ef62f6b3053
pdf-javascript-stream PDF /JS object 6 at offset 0x143 626597 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).