Malicious PDF — malware analysis report

Static analysis result for SHA-256 b3e912cb37ad259a…

MALICIOUS

PDF

118.5 KB
MD5: e239fd9ccb9a07841058e5e9b4ff1df0 SHA-1: 66cef5f5ef119c90ce6ffeffc94a31109c592755 SHA-256: b3e912cb37ad259ab99d1070dd8cedcd87b82e5830e185c1797799ca28ef7ecc
196 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript, including calls to eval() and String.fromCharCode, which are indicative of obfuscation and execution of malicious code. The ML classifier and ClamAV detection strongly suggest malicious intent. The primary attack vector appears to be exploiting a PDF vulnerability to run JavaScript, likely for downloading and executing further stages of malware.

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
8f3fffe1512aa53ada8d4f4e39159c47f2de80eaa846d3da803509c82d1f91f8
pdf-javascript-stream PDF /JS object 6 at offset 0x143 626897 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).
legacy_pdfkit_stage_000.js
e9d38fdcc8a73655f424695af4cd2caa2b5cad86a6efca395efd9372ce201748
deobfuscated-js double percent-decoded annotation JavaScript at offset 0x143 262144 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 557 long base64-like blob(s).