Malicious PDF — malware analysis report

Static analysis result for SHA-256 fbbca30ed0df7121…

MALICIOUS

PDF

3.4 KB First seen: 2026-05-10
MD5: 392b5aa44a1ccc4b9b273ccb635d7949 SHA-1: b2b956fc9d052e94e2d294cceaa6be4986151661 SHA-256: fbbca30ed0df7121fe4bad7b25d664067514c559a68fe2ec97544eddc1b2a02f
118 Risk Score

Malware Insights

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

The PDF document contains JavaScript and uses ASCIIHexDecode filters, which are common techniques for obfuscating malicious content. The ML classifier strongly indicates maliciousness. The combination of these factors suggests the PDF is designed to execute a malicious script, likely leading to the download and execution of a second-stage 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