Malicious PDF — malware analysis report

Static analysis result for SHA-256 e8ac436d0c299229…

MALICIOUS

PDF

4.9 KB Created: 2011-04-05 23:46:28 Authoring application: bub lob
MD5: 16aff13a3ff7e20c80559e8129fd62dc SHA-1: 5da768f883f555f3c1059f61865918875b970988 SHA-256: e8ac436d0c2992293e9aeadcd4c342980cd13b161237cf77d6851fc75041a092
68 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, indicated by the 'PDF_EMBEDDED_SCRIPT_PAYLOAD' heuristic. The ML classifier strongly flags this PDF as malicious. The embedded JavaScript, named 'stream_001_off00000331.js', is likely responsible for downloading and executing a second-stage payload, a common technique for initial access.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • Embedded script payload in PDF stream medium PDF_EMBEDDED_SCRIPT_PAYLOAD
    PDF stream bytes contain an HTML/XFA <script> tag without accompanying Windows shell-execution primitives — common in accessible XFA forms but worth surfacing for analyst review.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_001_off00000331.js
ca2b6c255b2a21bfd1a44c39e4655d31b1c600b1b26c438b14cddcc7955098e5
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x331 13527 bytes