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

Static analysis result for SHA-256 6b2f8681d59127bd…

MALICIOUS

Office (OOXML) / .XLSM

438.7 KB Created: 2000-04-13 21:48:14 UTC Authoring application: Microsoft Excel 12.0000
MD5: d0bec070e9807f62d8442da875844c43 SHA-1: d0096e006041c95a8d56c591f3bc5a81bac56ea1 SHA-256: 6b2f8681d59127bd3c655782370664e6ddc1f363cdda081bdc452151e3d0f10a
208 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The critical heuristic 'Obfuscated auto-exec VBA loader' and the high-severity 'Workbook_Open macro' firing indicate that the VBA code within this XLSM file is designed to execute automatically upon opening. The script constructs a path to a script file, likely `C:\Users\Public\getMonths2633.sct`, and then uses `mshta` to execute it, which in turn uses `Wscript.Shell` to run the script. This suggests a downloader or initial execution stage for a more complex payload.

Heuristics 6

  • 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.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_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
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
ae3d1e08d52c9e8483773dc464f96426fb73c6437d32620e73fa7cfe8bbf30c5		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1160 bytes
vbaProject_00.bin
471893c24922b2122e2b4a0a677a9a5c45d74a57f7e74a96e4fc4a2498379608		 vba-project OOXML VBA project: xl/vbaProject.bin 9216 bytes

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