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

Static analysis result for SHA-256 5d7c07035e5257a6…

MALICIOUS

Office (OOXML) / .DOC

21.9 KB Created: 2022-01-05 00:07:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2022-03-18
MD5: da9816b60d9866b1b6d90a8e20e39623 SHA-1: 685b49e2e1855f4a8b455a5969e4df02f5c75356 SHA-256: 5d7c07035e5257a64d546e69112d17d2eab977cca23e225cfcfc8ac59334aa78
202 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059 Command and Scripting Interpreter T1140 Deobfuscate/Decode Files or Information T1204.002 Malicious File

The sample contains a VBA macro that executes upon opening the document, leveraging a Document_Open subroutine. This macro uses obfuscated string concatenation to instantiate a WScript.Shell object and then calls a custom function 'GPA' to download and save a file named 'knla.dat' to the current directory. The 'GPA' function reconstructs binary data from custom document properties and saves it, likely as a second-stage payload. The technique of reassembling API names and using obfuscated strings is a common tactic for evading detection.

Heuristics 6

  • Dangerous API name reassembled from split string literals critical OLE_VBA_SPLIT_KEYWORD_OBFUSCATION
    VBA concatenates short string literals that reassemble a dangerous API/ProgID/LOLBin name (e.g. Scripting.FileSystemObject, WScript.Shell, powershell, URLDownloadToFile) which appears in no single literal. Splitting an API name across string concatenation is done only to evade keyword scanning.
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject 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 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.openxmlformats.org/markup-compatibility/2006
    • 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/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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
8e701549e52053487b243a609be8c6d876b85f0898fe17f088e742a73c46a3f4		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1371 bytes
vbaProject_00.bin
24c88c03d83924c70e0bb40b3d88003599893045a0106f55d3fa45be8f71a8d9		 vba-project OOXML VBA project: word/vbaProject.bin 31744 bytes

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