Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 5781e0077bae1a74…

MALICIOUS

Office (OLE) / .XLS

53.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-23
MD5: c666e863644c47dc2e4c3c680580ce5a SHA-1: 20431cbca44240b36518e470c1d55b1b493d4f8c SHA-256: 5781e0077bae1a7416d265210c3959c30438e76477b6b446967d2b75abf2fec8
200 Risk Score

Malware Insights

Emotet · confidence 95%

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

The file is detected as malicious by ClamAV and exhibits critical heuristic firings for Excel 4.0 macros, including an Auto_Open function that uses dangerous API calls like RUN. The Auto_Open macro is designed to download and execute a second-stage payload from one of the provided URLs. The presence of the Auto_Open function and the nature of the URLs strongly suggest a downloader functionality, consistent with the Emotet family.

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-b3b8ccc73b3840c7-9950421-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-b3b8ccc73b3840c7-9950421-0
  • 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
151b15ccfdef8b57d0d5c096b1dd2309f093b48372ced07c9ad7f3b360037185		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7313 bytes

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