Malicious PDF — malware analysis report

Static analysis result for SHA-256 9417d511eb663157…

MALICIOUS

PDF

2.2 KB
MD5: f95a832578cde8739fa3e1e3cb4ff61d SHA-1: 1fa08f8f18516f1ee8a7984f96a610da4df2c090 SHA-256: 9417d511eb663157c678e6cbb7f0cb8b5f7a5efa9f46a5ad73ca44341e61cbc6
196 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/JScript T1566.002 Spearphishing Attachment T1204.002 Malicious File

This PDF file was flagged by ClamAV as Pdf.Exploit.Agent-36082, indicating it contains a known exploit. Static analysis revealed embedded JavaScript with high-confidence indicators of malicious activity, including eval(), unescape(), and String.fromCharCode() calls. These functions are commonly used to deobfuscate and execute malicious code. The ML classifier also assigned a very high probability of maliciousness. The primary attack pattern involves exploiting PDF vulnerabilities to run embedded JavaScript, which is likely designed to download and execute a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 7

  • ClamAV: Pdf.Exploit.Agent-36082 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36082
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
  • 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_obj111611_000.js
772da696bdb365f3f1eb4ea6af881baad391be62f3591b19f2f9827fcc4c9b53
pdf-javascript-stream PDF /JS object 111611 at offset 0x7DC 479 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).
legacy_pdfkit_stage_000.js
fe42984301071b167ea298277289b1e0001e5421fc351d5d9fcb1de68698b2c5
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x189 2822 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).