Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 21668ccece2030f9…

MALICIOUS

Office (OLE) / .XLS

116.2 KB Created: 2022-01-24 15:38:16 Authoring application: Microsoft Excel
MD5: d6f9ec5105fbcac44e8561dc562d244c SHA-1: cf5b0172899ab2a73ea3666b349b344fc4e514a8 SHA-256: 21668ccece2030f9c90c0bf732601f26e2b95b533b71fdb7721ad3b9b24a384a
200 Risk Score

Malware Insights

Emotet · confidence 95%

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

The file is detected as malicious by ClamAV with the signature Xls.Downloader.Emotet-bd646319c2d29cd6-9951195-0, indicating it belongs to the Emotet family. Static analysis revealed Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code. This function likely downloads and executes a second-stage payload, consistent with Emotet's behavior.

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
78f4d10131fdda90a83ff9beee5f7492c2e7df589721df22ed313e9b7030dce3
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 5174 bytes