Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 c9d8651ed4473d6c…

MALICIOUS

Office (OLE) / .XLSX

115.3 KB Created: 2022-01-24 14:50:55 Authoring application: Microsoft Excel
MD5: a9a1683b7bd8ed7466fed4c0ca5c240b SHA-1: 6bd09d6c96b7514494bab428e6b9787621a4d0f1 SHA-256: c9d8651ed4473d6c45bf0c8ac7f5a94d127c87cf3b5cd06848218347ae7c2a2c
200 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1059.001 PowerShell

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a known technique for executing malicious code. ClamAV identifies the file as 'Xls.Downloader.Emotet-bd646319c2d29cd6-9951195-0', strongly suggesting Emotet family involvement. The Auto_Open macro likely serves to download and execute a second-stage payload.

Heuristics 4

  • 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.
  • ClamAV: Xls.Downloader.Emotet-bd646319c2d29cd6-9951195-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-bd646319c2d29cd6-9951195-0
  • 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
f65423032a2492710482664c048191ebe835ee4ace2752f1b0fa6e40d416cdf9		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 4885 bytes

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