Malicious PDF — malware analysis report

Static analysis result for SHA-256 b598adf2a40e20d5…

MALICIOUS

PDF

118.4 KB
MD5: e140af367620dfb7bfe5b77cb2a98fc9 SHA-1: 302506bddf5a6083e6d56de208b81c26452650ae SHA-256: b598adf2a40e20d5efcfd7c90293a199cc2a71a2424da0c1a59b1658b297f421
196 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript, indicated by multiple heuristic firings including 'PDF_JAVASCRIPT', 'PDF_JS', and 'PDF_EVAL'. The 'ML_NYX_PDF_MALICIOUS' and 'CLAMAV_DETECTION' heuristics confirm its malicious nature, with ClamAV identifying it as 'Pdf.Exploit.Agent-36086'. The presence of 'PDF_JS_LARGE_COMMENT_PADDED_EVAL' suggests a stager designed to obfuscate and execute malicious code, likely to download and run a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

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
db256ec927d1aff665377f730f17c9432c7d4745e14f049c485ec6c5bae5b3b2
pdf-javascript-stream PDF /JS object 6 at offset 0x143 626735 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_001_off0001d641.bin
d5e486ae7257da06b47eea613ca7f8d832b3f5008e26651596098220d67839c3
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1D641 300 bytes