Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 be9310fd0b884c49…

MALICIOUS

Office (OOXML)

41.8 KB Created: 2021-06-22 12:43:05 UTC Authoring application: Microsoft Excel 16.0300
MD5: f20108a7f20d3b4a13794703d5689525 SHA-1: 6bbb9d0fac995f110bc072aee3bb7927e35375c1 SHA-256: be9310fd0b884c4947ba607a8d7a90229e9928bcca7a0919ab3b56cfd0e7c532
260 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1218.011 System Binary Proxy Execution: Rundll32

The file is an Office document containing VBA macros. The Workbook_Open macro triggers the execution of PowerShell commands, as indicated by the OLE_VBA_PS and OLE_VBA_CMD heuristics. The critical OLE_VBA_WMI_PROCESS_CREATE heuristic specifically points to the use of WMI to launch processes, likely for downloading and executing a secondary payload. The Decode64 function suggests potential obfuscation of the payload.

Heuristics 6

  • PowerShell reference in VBA critical OLE_VBA_PS
    PowerShell reference in VBA
  • VBA WMI Win32_Process launcher critical OLE_VBA_WMI_PROCESS_CREATE
    VBA macro builds or references a WMI moniker for Win32_Process and invokes .Create to start a command. This is a high-confidence macro execution chain that often hides the WMI class name through string concatenation or helper functions.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
  • cmd.exe reference in VBA high OLE_VBA_CMD
    cmd.exe reference in VBA
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
316f0c5c90af1a7923d009e6c97a76bf819ebc28b50c9ee21f47b40945b8c547		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 35248 bytes
vbaProject_00.bin
f4301771056a0ba2bbe4b79e62df2d77b58e235d45391fb72a51d58cf6676802		 vba-project OOXML VBA project: xl/vbaProject.bin 11264 bytes

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