Malicious PDF — malware analysis report

Static analysis result for SHA-256 20734739d3f873bc…

MALICIOUS

PDF

4.9 KB Created: 2011-04-05 23:46:28 Authoring application: bub lob
MD5: fbb6260fca2b1aedf02fed4f6e5b1f81 SHA-1: 817ddad4b7724bd4a39b9a9d60888a51d7c40124 SHA-256: 20734739d3f873bcebfc9a959b422ad50914496dc8266f2ab57fd8a8dc8f43fa
68 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1566.002 Spearphishing Attachment T1059.001 PowerShell

The PDF contains an embedded script payload, indicated by the PDF_EMBEDDED_SCRIPT_PAYLOAD heuristic. The ML classifier strongly flags this PDF as malicious. The embedded JavaScript file, stream_001_off00000331.js, is likely responsible for executing the malicious payload, although its specific actions are not detailed in the provided evidence.

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
14009cfd15aac3c86e2f6bfbce217e9fd2fd2b02b07620183654e6235fbfad31
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x331 13525 bytes