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

Static analysis result for SHA-256 d297f78ca4fc35e8…

MALICIOUS

Office (OOXML) / .DOC

2.19 MB Created: 2022-08-11 13:43:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2022-08-11
MD5: db11828aed458eccfab30c367bc1bb2f SHA-1: 3487931f130485c82d21e9ef4155af0a8fd46c33 SHA-256: d297f78ca4fc35e899792260c98f752947f7d6b5999650a6210f4a8538a2e655
362 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File T1140 Deobfuscate or Obfuscate

The sample is an OOXML document containing a VBA macro that is obfuscated and uses a shellcode loader technique. The macro is triggered by the Document_Open event and attempts to execute code in memory. The document also contains a lure to enable macros, which is a common tactic for malware droppers. The ClamAV detection ID further supports its malicious nature.

Heuristics 10

  • VBA property-stored shellcode loader critical OLE_VBA_PROPERTY_SHELLCODE_LOADER
    VBA auto-exec macro takes the address (VarPtr) of a byte buffer decoded from a document property, marks memory executable (VirtualProtect/VirtualAlloc), and transfers control through a callback API (e.g. SetTimer/EnumWindows). The payload is hidden in the document properties rather than the macro source — the SVCReady loader pattern, a native shellcode runner rather than a parser CVE.
  • ClamAV: Doc.Downloader.af2f0393915c6ce8-OOXML-9981526-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.af2f0393915c6ce8-OOXML-9981526-0
  • VBA project part renamed to evade filename detection high OOXML_VBA_PROJECT_RENAMED
    The VBA project is bound through the OOXML relationship/content type but its part is not named vbaProject.bin. Legitimate Office producers always emit vbaProject.bin; renaming it hides the macros from path-only scanners (observed in the SVCReady loader).
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
  • CallByName call high OLE_VBA_CALLBYNAME
    CallByName call
  • VBA reads reversed config from document properties high OLE_VBA_REVERSED_DOCPROP_CONFIG
    VBA applies StrReverse to values read from the document's custom/built-in properties. Storing reversed configuration (URLs, CLSIDs, env-var names, payload names) in document properties keeps indicators out of the macro source — an obfuscation technique used by the SVCReady loader.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present (project part renamed away from vbaProject.bin: word/tzfEATNsQT.bin)
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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.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/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
b5530ef490a8e152c86a373505d141410f58f0d08d86081aeaa14b7ebefc3f9e		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 21157 bytes
vbaProject_00.bin
b9f80d39ec36e6c955ba05782840763d28e1cf6a9fa3dcfde55fdf95100efddc		 vba-project OOXML VBA project: word/tzfEATNsQT.bin 14848 bytes

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