Malicious PDF — malware analysis report

Static analysis result for SHA-256 a617e87ee00bd257…

MALICIOUS

PDF

26.5 KB Created: 2011-02-03 12:46:29 +02:00 Authoring application: Rv Loan Interest Rate Wiki (via mPDF 5.0)
MD5: a67874458d6bd3a5e1a0c2f3fa21b2fc SHA-1: 1f9fd1fae366075ceeb3cf8f90656e27805f5496 SHA-256: a617e87ee00bd257fc8bb4c74282a4416fc1404637db87b51d92a5a825f742e3
106 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including PDF_JAVASCRIPT and PDF_JS. The ML classifier strongly flagged this PDF as malicious. The extracted JavaScript files, javascript_obj0020_000.js and javascript_obj0020_001.js, show signs of obfuscation and likely contain code to download and execute a second-stage payload. The presence of unescape() calls further supports the obfuscation technique.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9995

Heuristics 4

  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits
  • Suspicious extracted artifact medium 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.
  • 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.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0020_000.js
357d06d70777f397a54fd04180a5ee36f36a8ec5c7cbbafdfab41f20901b25ac
pdf-javascript-stream PDF /JS object 20 at offset 0x62C5 136 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long hex-escaped blob(s).
javascript_obj0020_001.js
607a0753f2d28ea7a383d2e729ee9a1eeb69db22eafb74fa3e1d444ae047c123
pdf-javascript-stream PDF /JS object 20 at offset 0x62C5 134 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long hex-escaped blob(s).