Malicious PDF — malware analysis report

Static analysis result for SHA-256 4964023d7a0f516f…

MALICIOUS

PDF

15.8 KB
MD5: 6f0080a4e4d4fed46c8aa08b03c68683 SHA-1: fb8c8d34bae31eb75f0891b09f6abd90dda4e69e SHA-256: 4964023d7a0f516f7c5deef82b6c4b23f453b438d5b47fef9f4630cfcbff330d
166 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, including a large comment-padded eval stager. This indicates the file is designed to exploit vulnerabilities within PDF viewers to execute arbitrary code. The presence of `eval()` and `String.fromCharCode` suggests obfuscated JavaScript is used to achieve this. The ClamAV detection of 'Pdf.Exploit.Agent-36086' further confirms its malicious nature, likely involving the download and execution of a second-stage payload.

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
3cb6d900f11efae1593e06e5891dadbfb8865cc33bce1cadf58e93f02aae914e
pdf-javascript-stream PDF /JS object 6 at offset 0x143 425843 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).