Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 497363662235014c…

MALICIOUS

Office (OLE) / .XLSX

94.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-24
MD5: 77138b11c2ef691fa586db758681f5fa SHA-1: ea2ace84e9cc1da4a145e73f8cd0409118169a05 SHA-256: 497363662235014ca73c20d8ee9b4c2e1ad7a1b9055a9dd0134392de310d9082
200 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1204.002 Malicious File T1059.001 PowerShell T1105 Ingress Tool Transfer

The sample 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, and the presence of dangerous formula APIs like RUN further supports this. The macro is designed to download and execute a second-stage payload from one of the provided URLs, a common Emotet delivery mechanism.

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