Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 3ad3957e821fe03b…

MALICIOUS

Office (OOXML)

434.6 KB Created: 2021-07-28 10:37:27 UTC Authoring application: Microsoft Excel 12.0000
MD5: 9981389c81be717bf580172c4e6389a1 SHA-1: d4f70ace4dbce38447152da925304381be61e98b SHA-256: 3ad3957e821fe03b9ee944d3e047de00f22bf15fbf463026e2c6dd4f47999e78
208 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059 Command and Scripting Interpreter T1204.002 Malicious File T1566.001 Spearphishing Attachment

The critical heuristic 'OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER' and the high-severity 'OLE_VBA_WBOPEN' indicate a malicious macro loader. The Workbook_Open subroutine constructs a path to a SCT file using environment variables and sheet data, then uses CreateObject to execute it via 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
5668a638ab00fa3002e04ebadff42d76557251da9e47675567acc30bfa2f2bda		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1123 bytes
vbaProject_00.bin
46faf001649579a8da4935f7ea9e3f32a0c721050d46474b2b725f693e01581c		 vba-project OOXML VBA project: xl/vbaProject.bin 9216 bytes

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