Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 7e435cdbbccadf97…

MALICIOUS

Office (OLE) / .XLSX

55.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-23
MD5: e5a2a8d01a34de06a3e9fced40fd252c SHA-1: fb9bff3dc4db618b9be8cec0d5eb1fc4c71f5ed7 SHA-256: 7e435cdbbccadf97e1fb263a0099d11d74db5845822169fa39511918a5915756
200 Risk Score

Malware Insights

Emotet · confidence 95%

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

The sample contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code. The macro uses the RUN API to execute a URL, which is reconstructed as "http://ora.es/tmp/vi98YEQq/". This indicates the file is a downloader, likely for the Emotet family, designed to fetch and execute a secondary payload. The presence of the Auto_Open function and the RUN API call strongly suggests malicious intent.

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-aa87d5786a858772-9953435-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-aa87d5786a858772-9953435-0
  • 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
8a1b85527405f075bb91c56ecfcdd451eb9c43d1e0bc4e5b91a53261cb41b850
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8028 bytes