Malicious PDF — malware analysis report

Static analysis result for SHA-256 b48a81f998af7af8…

MALICIOUS

PDF

3.4 KB First seen: 2026-05-10
MD5: 463fdc11092a3831b80ee1cc04b29989 SHA-1: 6b4425875ef8ac166f8e9e31e71adfdc875f6a93 SHA-256: b48a81f998af7af810b22fb0678dfca318a7e1270e9d726e64e051ed45de9d85
118 Risk Score

Malware Insights

MITRE ATT&CK
T1059.003 JavaScript T1559.002 Component Object Model

The ML classifier strongly indicates maliciousness, supported by heuristics for JavaScript actions and ASCIIHexDecode filters, which are commonly used in PDF exploits. The presence of JavaScript suggests an attempt to execute malicious code, likely to download a second-stage payload or exploit a vulnerability within the PDF reader.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 3

  • JavaScript action low 1 related finding PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • PDF JavaScript rebuilds a builtin via replace() to run a char-code array critical PDF_JS_REPLACE_OBFUSCATED_CHARCODE_BUILDER
    Decoded PDF JavaScript resolves a String builtin from a junked literal — e.g. String['eQvoaol3'.replace(/[3oQS5]/g,'')] yielding fromCharCode/eval — and feeds a large numeric char-code array through it to rebuild and execute the next stage. Dynamically reconstructing a builtin name by stripping junk characters has no benign purpose; paired with the char-code payload array it is an unambiguous obfuscated-JavaScript exploit dropper.
  • ASCIIHexDecode filter (with exploit indicators) medium PDF_FILTER_HEX
    Hex-encoding filter present alongside exploit delivery indicators — often used to hide payload or shellcode bytes