Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 da73beee823e4d48…

MALICIOUS

Office (OLE) / .XLS

142.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-03-25
MD5: a5077b56aa90c836ead6a806aafd9c03 SHA-1: 0e0c70a958f8dac27bd4762705a3798c6d8824fe SHA-256: da73beee823e4d4897f4dea43efc4c1a8e92c1ae5419753d81f8030e735f7bd2
200 Risk Score

Malware Insights

Emotet · confidence 95%

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

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code. The ClamAV detection explicitly names Emotet. The macro constructs several strings that appear to be URLs, likely for downloading a secondary payload. One reconstructed URL is 'Sy"&"s"&"W"&"o"&"w"&"64\\\[truncated]d"&"ear"&"dar"&"cy.c"&"o"&"m/c"&"s"&"s/N"&"H"&"G"&"yT"&"TC"&"K/', which is indicative of a downloader attempting to execute a file.

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-adc2d23d2dc26dd0-9950240-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-adc2d23d2dc26dd0-9950240-0
  • 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
eee0a3dec225fd0088c74c7ab34b064dd06b0d4f7198f4d9a113e7b902ce722a		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6706 bytes

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