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

Static analysis result for SHA-256 160f120cab1d34c0…

MALICIOUS

Office (OOXML) / .XLSM

439.1 KB Created: 2021-07-28 10:37:27 UTC Authoring application: Microsoft Excel 12.0000
MD5: bb4d56f3097ef6e275108a18708fc95f SHA-1: fa30c32c2f36a81e435b6dac162e3999d32c52b9 SHA-256: 160f120cab1d34c03141ab1a4780786d52aa40f6ab3387d578df89563f595d1f
208 Risk Score

Malware Insights

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

The critical heuristic 'OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER' indicates an obfuscated auto-exec VBA loader. The WorkBook_Open macro is triggered upon opening the document, which then constructs a path to a script file using environment variables and cell data. It writes this script to a file and then executes it using 'mshta'. This indicates the document is designed to download and execute a second-stage 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
a495d13f908b936d14fd405911fbbb58425fd23c6aabe6af8daecb616e33d5dc		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1124 bytes
vbaProject_00.bin
ce2b2076107580d2525d5bc99c5e4ab9f02133ca93844e797106d0b5d0889d93		 vba-project OOXML VBA project: xl/vbaProject.bin 9216 bytes

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