Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 78cd02f4a929c3f0…

MALICIOUS

Office (OLE) / .XLSX

127.6 KB Created: 2022-01-17 21:27:03 Authoring application: Microsoft Excel
MD5: b55e5a5df6c920d669a528eb19f3dc99 SHA-1: c570a04850d744f5a48810d5b2c288aae1899a42 SHA-256: 78cd02f4a929c3f02251fa14eb043fb361137bf3d7696254ea6554e24aaccae1
140 Risk Score

Malware Insights

Emotet · confidence 95%

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

The sample contains Excel 4.0 macros with an Auto_Open entry, a known Emotet delivery technique. The macro executes a command to download a payload from a obfuscated URL. The reconstructed URL is http://c12a24f5/cc.html, which is likely the initial stage of a Emotet infection chain.

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

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