Malicious PDF — malware analysis report

Static analysis result for SHA-256 e57f139b16aedb88…

MALICIOUS

PDF

15.8 KB
MD5: 8846503c01369caea3a8a191a3412e47 SHA-1: 823dcc1ce9451b0b4c63ef64825d3d96dc22115a SHA-256: e57f139b16aedb88b7ed2ef377d13f5c0a9f05b9d6e49f997ca1609fc79272bb
166 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that utilizes eval() and String.fromCharCode, indicating an attempt to obfuscate malicious code. The presence of a 'Large comment-padded JavaScript eval stager' heuristic firing, along with ClamAV detecting it as 'Pdf.Exploit.Agent-36086', strongly suggests this is a malicious PDF designed to exploit vulnerabilities. The embedded JavaScript, named 'javascript_obj0006_000.js', is the primary artifact likely responsible for executing the exploit, potentially leading to the download of further malicious content.

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
5a2001489348efa4aeced7d4bfc49f96ebf5b339fc1479563458f2889e58b883
pdf-javascript-stream PDF /JS object 6 at offset 0x143 425928 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).