Malicious PDF — malware analysis report

Static analysis result for SHA-256 83705281cafd2304…

MALICIOUS

PDF

4.0 KB
MD5: 0c849eabe460466a4e7ee1ad9190443f SHA-1: 20ebd25963c5eaaa52586678607ca1015b827674 SHA-256: 83705281cafd2304251bdeec147f5e202ef9b93dbe53e4ac86281fb6a5b4c867
76 Risk Score

Malware Insights

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

This PDF sample contains embedded JavaScript, indicated by PDF_JAVASCRIPT and PDF_JS heuristics. The ML classifier strongly flags it as malicious. The JavaScript appears to be obfuscated but contains an `eval` call that likely executes a dynamically constructed string, potentially downloading and running a secondary payload. The reconstructed string `eval(a.split(" ").join(""))` is the primary IOC.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 5

  • 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
  • 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.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.