Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 28a51bf5543949a0…

MALICIOUS

Office (OLE) / .XLSX

142.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-03-25
MD5: 97a1eb30bfb5e5de5bbc7cd268eb2dd2 SHA-1: d967f27189c46fda14d497c1d0bf5cc444060079 SHA-256: 28a51bf5543949a04b8aae81ce8a72e80d5b7d721e3810153bfd287a3b84ab91
200 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic 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 macros construct a command to run 'svrr32.exe' and 'cmd.exe' with arguments that appear to be URLs, suggesting a downloader functionality. ClamAV also identifies this as an Emotet variant, reinforcing the malicious intent. The reconstructed command string is "&"e"&"g"&"sv"&"r3"&"2.e"&"x"&"e Sy"&"s"&"W"&"o"&"w"&"64\Windows\System32\cmd.exe

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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