Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 b8d4a81dbfaa3f89…

MALICIOUS

Office (OLE) / .XLS

94.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-24
MD5: f4d53ef3c6c3e4fedbfdfb7e03ee4205 SHA-1: 635e2dd1c5517b4969512511935a726fe998c0b6 SHA-256: b8d4a81dbfaa3f8908c3c23b47724156309e3b0d2b83fadcdece18b41f665918
200 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Service Execution: Service Execution T1059.001 PowerShell: PowerShell

The sample contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a known technique for executing malicious code. The ClamAV detection explicitly names Emotet, and the presence of URLs suggests a downloader functionality. The XLM Auto_Open macro uses dangerous formula APIs, including the RUN function, to likely download and execute a second-stage payload from the provided URLs.

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-b2cbc93e36c0c13e-9950560-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-b2cbc93e36c0c13e-9950560-0
  • 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
2ca0966e93dacad101ceb18f4d58731b5432892fe851526f2fda59486181312c		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7325 bytes

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