Malicious PDF — malware analysis report

Static analysis result for SHA-256 c138314c27c0bd2c…

MALICIOUS

PDF

118.7 KB
MD5: 32d3ff1c2e8fde6c11242a71a4b55606 SHA-1: c2206c6cf21b8aa93d0693ca9c4bf5d0dacf419e SHA-256: c138314c27c0bd2c29e9ffa4280ff26d0100c4e551e34b2d75d40e000538b83f
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1566.001 Spearphishing Attachment

The PDF file contains embedded JavaScript, including a large comment-padded eval stager. This JavaScript is designed to execute arbitrary code, as indicated by the 'eval()' and 'String.fromCharCode()' calls. The ClamAV detection 'Pdf.Exploit.Agent-36086' further confirms its malicious nature. The primary attack vector appears to be exploiting a PDF vulnerability to achieve code execution, likely for downloading additional malware.

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
4f8d9e8e7327d8cec3a96fe041f2a0ab4470612a60c74f20665149229017c021
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627506 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).