Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 c45bf0bf43d9595b…

MALICIOUS

Office (OLE) / .XLS

94.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-29
MD5: bca774464f52e484a93f3841124758a1 SHA-1: 1bf6b435f6389af53744e960dac2e643eaac4192 SHA-256: c45bf0bf43d9595be252f2646198e686ee50df78f2eafd8fd58f5fda324db8b5
200 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Service Execution: Service Execution T1059.001 PowerShell: PowerShell T1204.002 Malicious File: User Execution: Malicious File

The sample is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro that utilizes dangerous functions, including 'RUN', suggesting it's designed to download and execute a second-stage payload. ClamAV detection confirms this, identifying it as an Emotet downloader variant.

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-ea81817e7f807ab1-9952142-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-ea81817e7f807ab1-9952142-0
  • 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
4ea59aaf1865fd22462c445093f6945cf0062104396bd949b0a99cab86de5a66		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8158 bytes

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