Malicious PDF — malware analysis report

Static analysis result for SHA-256 c309becb341e21f0…

MALICIOUS

PDF

4.9 KB Created: 2011-04-05 23:46:28 Authoring application: bub lob
MD5: 354d762ccd7346d52232c240417402f3 SHA-1: 8de7b82ca218afb6c0d2e56ed9d0b116f8debcca SHA-256: c309becb341e21f0bca83103274c7c0f5777e519e53a27851d4d47409c417d66
68 Risk Score

Malware Insights

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

The PDF file contains an embedded script payload, indicated by the 'PDF_EMBEDDED_SCRIPT_PAYLOAD' heuristic. The ML classifier also strongly flagged this PDF as malicious. The embedded JavaScript file, 'stream_001_off00000331.js', is likely responsible for executing the malicious payload, potentially exploiting a vulnerability within the PDF reader.

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
5e1a4a58f028f7fa9e1bde1de780790d90ac911f6c7e555f0e6b80e0b87e79ca
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x331 13557 bytes