Malicious PDF — malware analysis report

Static analysis result for SHA-256 fd5b65c5a52c0a85…

MALICIOUS

PDF

3.4 KB First seen: 2026-05-11
MD5: ae5c6c37bcc46fccd0bb2626bb452c1f SHA-1: 7e829138b68017672e68f5daabb430012966665d SHA-256: fd5b65c5a52c0a8562ce1283e234b3d6a8d2096b78cfa7fa61edbd2a80934d76
118 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript and uses ASCIIHexDecode filters, which are common techniques for obfuscating malicious content within PDF documents. The ML classifier strongly indicates malicious intent. While no specific family is identified, the combination of these factors suggests an attempt to exploit a PDF vulnerability, likely to download and execute a secondary payload.

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