Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 a65c63b224eb230e…

MALICIOUS

Office (OOXML)

440.2 KB Created: 2021-07-28 10:37:27 UTC Authoring application: Microsoft Excel 12.0000
MD5: 03d92749d7a35e13114af2838237cb26 SHA-1: 747b5888fd7f28efca75b8250009ae4a8aec19aa SHA-256: a65c63b224eb230eb6085192b212fdf8e680ad4277c136aa91245636c99c18af
208 Risk Score

Malware Insights

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

The sample is an Excel document containing an obfuscated Workbook_Open VBA macro. This macro constructs a path to a script file using environment variables and sheet data, then executes it using 'mshta' via CreateObject. The script file is likely a second-stage payload, indicated by the use of 'mshta' and 'Wscript.Shell' in the DOC BODY and the critical heuristic 'OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER'.

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
96eb5adcd62e338cccbdeb277a8e892c36a712a35f242d55931fbc39f1141775		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1128 bytes
vbaProject_00.bin
97f81c27c49e2bab7596d80e76b8bd50dfcd0ea2831ce92d146dcf18fd7cf08f		 vba-project OOXML VBA project: xl/vbaProject.bin 9216 bytes

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