Malicious Office (OOXML) / .DOC — malware analysis report

Static analysis result for SHA-256 134b6a1a057a66cf…

MALICIOUS

Office (OOXML) / .DOC

41.7 KB Created: 2020-10-23 14:01:00 UTC Authoring application: Microsoft Office Word 16.0000
MD5: 7dfbc46ade7f1ce8c940a4ebf01a682c SHA-1: 6ebbf886a45f37e370a7a809c35e40a3717e12e3 SHA-256: 134b6a1a057a66cf663abb6311a7f795b425de6f0d19ead388d46cdc9a7c3d49
342 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1071.001 Web Protocols

The sample is a malicious OOXML document containing an obfuscated auto-executing VBA macro named 'Document_Open'. This macro uses GetObject and a custom decoder ('Fenian' function) to retrieve and execute a payload from a variable within the document. The 'Mohair' subroutine likely handles the execution of the downloaded payload, indicating a downloader functionality. The presence of VBA macros and the 'Document_Open' auto-execution strongly suggests a macro-based malware delivery.

Heuristics 9

  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • ClamAV: Doc.Downloader.Sagent-9770108-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Sagent-9770108-0
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Embedded OLE object medium OOXML_OLE_OBJECT
    Document contains an embedded OLE object
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.microsoft.com/office/word/2010/wordprocessingCanvas
    • http://schemas.microsoft.com/office/drawing/2014/chartex
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartex
    • http://schemas.microsoft.com/office/drawing/2015/10/21/chartex
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartex
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartex
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartex
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartex
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartex
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartex
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.microsoft.com/office/drawing/2016/ink
    • http://schemas.microsoft.com/office/drawing/2017/model3d
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/officeDocument/2006/math
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawing
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing
    • http://schemas.openxmlformats.org/wordprocessingml/2006/main
    • http://schemas.microsoft.com/office/word/2010/wordml
    • http://schemas.microsoft.com/office/word/2012/wordml
    • http://schemas.microsoft.com/office/word/2016/wordml/cid
    • http://schemas.microsoft.com/office/word/2015/wordml/symex
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroup
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInk
    • http://schemas.microsoft.com/office/word/2006/wordml
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShape

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
b7204ce2e0b2ff020dea405dafd7afd89339c3ddad5986f56e5fdd677465ba94		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 3127 bytes
ooxml_oleobject_00.bin
9ee1c4a41a302249528c0944489fbeec592eabb48865fc701a411277a2cc34b5		 ooxml-ole-object OOXML embedded OLE part: word/embeddings/Microsoft_Word_Document.docx 15939 bytes
vbaProject_00.bin
4e336e1d91b123d213d73e97454eb497ff3ddfcff43364f18c5bece6a99580b4		 vba-project OOXML VBA project: word/vbaProject.bin 13312 bytes
Detection
ClamAV: Doc.Downloader.Sagent-9770108-0
Obfuscation or payload: unlikely
emf_00.emf
8b20b887ebb7fe5703eba60124d0c91c891d6201d31e68ed7f6aae0252c1c7eb		 ooxml-emf OOXML EMF part: word/media/image1.emf 31176 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.