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

Static analysis result for SHA-256 a665e96dd71fdeeb…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:36:56 Authoring application: Microsoft Excel
MD5: 34a6aab90e19e11d3068eba27155ff29 SHA-1: c1ab082379e8b24c702ad96dda6847c5f26dce25 SHA-256: a665e96dd71fdeeba876557db7baaad535c132154edb648301dd9b050f587760
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The sample contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. The heuristics indicate the use of dangerous formula APIs, including the 'RUN' function, suggesting the macro is designed to execute arbitrary commands. This is a common technique for downloading and executing further malicious content. No specific family could be identified, but the attack pattern is clear.

Heuristics 3

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
3a756ea22abdbe0f4852d0aac73565b31e5687334b600b66fdfa8d5c627ba99f
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6709 bytes