Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 4b9528fe4b8dda08…

MALICIOUS

Office (OLE) / .XLS

94.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-07-04
MD5: fe939d51aceae1251e93abd856126f5f SHA-1: f6af11618bede16765de4dbf1fed2cf6befe05ab SHA-256: 4b9528fe4b8dda082aa49f005ae11b43bc6c9769c7da3c14e7630bf155950612
200 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1059.001 PowerShell T1204.002 Malicious File

The sample is an Excel 4.0 spreadsheet containing an Auto_Open macro, identified by critical heuristics. ClamAV detection explicitly names it as 'Xls.Downloader.Emotet-ea81817e7f807ab1-9952142-0', indicating its function as a downloader for the Emotet family. The macro uses the RUN function, a known dangerous API for executing arbitrary code.

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
284f2836f30d4f529f3f67110b3bfb73d5b26e67c353e36fa87f86510408efa8		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8144 bytes

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