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

Static analysis result for SHA-256 154c09a68c7f1860…

MALICIOUS

Office (OOXML) / .XLSX

14.3 KB Created: 2020-05-25 09:20:33 UTC Authoring application: Microsoft Excel 15.0300
MD5: e969acde6033f405c249be3ba933af1f SHA-1: 10f5c2b1a862dd9905300d60aa03ab41e50ab61f SHA-256: 154c09a68c7f1860717c387fa83fc21166d4284973cb2103497e45d24c7dfb31
320 Risk Score

Malware Insights

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

This XLSX file contains a Workbook_Open macro that triggers obfuscated VBA code. The script utilizes WScript.Shell to execute commands, indicating a likely downloader or initial execution stage. The use of obfuscation and auto-execution suggests a malicious intent to run further payloads.

Heuristics 7

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • 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

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
c641f1ab89460039a53647177b1ecd1928107eeb473912231a8cd8b475638586		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 3564 bytes
vbaProject_00.bin
8213f59814f1e303e3835177f68d9b1c966a96f69bd226a702486bbedf855d3f		 vba-project OOXML VBA project: xl/vbaProject.bin 18432 bytes

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