Malicious PDF / .TXT — malware analysis report

Static analysis result for SHA-256 8919bba8913a5623…

MALICIOUS

PDF / .TXT

37.8 KB Created: 2010-04-15 17:17:40 +04:00 Authoring application: TCPDF (via TCPDF 4.8.032 (http://www.tcpdf.org))
MD5: a9a8975a73abb11d708805e53d41f37f SHA-1: 16d9efdbf7dd00cb64677b5af7dbb0fc08e82858 SHA-256: 8919bba8913a5623bf678d9494d49fb7bd6d92b0775b922a3b49b79705069ff6
114 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ClamAV as Pdf.Exploit.Agent-22718 and by an ML classifier as malicious. It contains embedded JavaScript that is obfuscated but appears to reconstruct a string and execute it via `app.setTimeOut`. This JavaScript likely downloads and executes a second-stage payload, a common technique for exploiting PDF vulnerabilities. The specific exploit used is not detailed, but the presence of JavaScript and the ML/ClamAV detections strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 4

  • ClamAV: Pdf.Exploit.Agent-22718 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-22718
  • 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.
  • Optional Content Group with action trigger low PDF_OPTIONAL_CONTENT
    Optional Content Group (layer) co-occurs with an action trigger — content can be selectively hidden from viewers or scanners while the action still fires on open

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0010_000.js
5df9d333488e8816fadd73fb0b29c172d463fb153e5eeae581d9544e3ebc4173
pdf-javascript-stream PDF /JS object 10 at offset 0x8CE8 1346 bytes