Malicious PDF — malware analysis report

Static analysis result for SHA-256 fbbc905ca1f2d4b5…

MALICIOUS

PDF

118.5 KB
MD5: b03b22c17157e143fefffdd7a3af854c SHA-1: d9e6f79616ff78aaaa6754b97ab26507effe4f50 SHA-256: fbbc905ca1f2d4b50bd598c4647ab0e0bbbeb863cccc4db0121cf592bc4b2ada
166 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that utilizes eval() and String.fromCharCode, indicating an attempt to obfuscate malicious code. The heuristic 'PDF_JS_LARGE_COMMENT_PADDED_EVAL' strongly suggests a stager designed to download and execute further content. ClamAV detection as 'Pdf.Exploit.Agent-36086' confirms its malicious nature. The lack of readable document body text prevents a more specific determination of the lure, but the technical indicators point to a typical exploit delivery mechanism.

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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0006_000.js
73fd9338321f6ac4aa2f4f52b4f691f5a949bf158bc1a8b3fe74764814294adf
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627154 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).
stream_002_off0001d834.bin
949415497b4a0614ff3212af142aaa4336c053c83c716a0ce81e3098c9431906
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1D834 200 bytes