Malicious PDF — malware analysis report

Static analysis result for SHA-256 0990abd5205e5113…

MALICIOUS

PDF

6.3 KB
MD5: a716b349a45b8209ae5ae0c227114efe SHA-1: 77adc341ac4a29553882033a740415f42c482750 SHA-256: 0990abd5205e51132458232ad58ca9782cd59d7250e37789ce2eb05a57fd3f91
268 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF sample contains obfuscated JavaScript that leverages the CVE-2008-2992 vulnerability, indicated by the 'util.printf' function and the PDF_JS_EXPLOIT_CLUSTER heuristic. The JavaScript is likely designed to download and execute a second-stage payload, as suggested by the ML classifier and ClamAV detection. The exact URL or payload could not be determined due to obfuscation and truncation.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 7

  • util.printf — CVE-2008-2992 critical CVE exact CVE_2008_2992
    PDF JavaScript calls util.printf() — CVE-2008-2992 is a stack buffer overflow in Adobe Reader triggered by a long format-specifier argument. Widely exploited in the wild after disclosure. (matched in decompressed stream)
  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
  • ClamAV: Heuristics.PDF.ObfuscatedNameObject critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Heuristics.PDF.ObfuscatedNameObject
  • 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.
  • 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0006_000.js
b769e4dd385e38d3b4daba346f34f657d0b61440c51122d7242ee99b453b308f
pdf-javascript-stream PDF /JS object 6 at offset 0x199 5395 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).