Malicious PDF — malware analysis report

Static analysis result for SHA-256 cd3beec4fe0383d1…

MALICIOUS

PDF

3.4 KB First seen: 2026-05-11
MD5: b6df0386a1aea5e905e3dca33c912ca2 SHA-1: 61832545868f4e3cfecc00d0a337daec2a55550b SHA-256: cd3beec4fe0383d1a40d4e6297b9466e359de49865f6f4b0e1263cd5f5e34877
118 Risk Score

Malware Insights

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

The ML classifier strongly indicates maliciousness, supported by heuristics for JavaScript actions and ASCIIHexDecode filters 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