Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 c3cac19c2603d25b…

MALICIOUS

Office (OLE) / .XLS

115.0 KB Created: 2022-01-24 01:40:11 Authoring application: Microsoft Excel
MD5: 02a9b582817612bc44e41d0629252792 SHA-1: 6b828a11db11bfab13303856c1e5256faac5f441 SHA-256: c3cac19c2603d25bde4eb88bfd088d2370bbce2cfbaeb92deaa50747f0a688c2
200 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The file is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro that utilizes dangerous functions, specifically the RUN function, which is commonly used to download and execute secondary payloads. ClamAV detection confirms this as Emotet, a known downloader family. The macro sheet contains an Auto_Open defined name, triggering the malicious execution path.

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
86637063ac2c97bbefdbc9033f21cd30e9484ed274aba63ad50d62dfa1de93cd
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 4341 bytes