Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 1c5f2ca983907874…

MALICIOUS

Office (OLE) / .XLS

255.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-11-07
MD5: 893f9b10a48073fc3fa0d5c8867f7200 SHA-1: 875d63ddc7467890f8f72aa787298ca4b2051e3e SHA-256: 1c5f2ca9839078742383b207721ce92fdfa70ac50e5d7b73c2488d47f7e5ebac
200 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a known technique for executing malicious code. ClamAV detection identifies this as Emotet, a downloader family. The presence of the Auto_Open function and the critical heuristic firings strongly indicate a malicious downloader.

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-b649c93692b4c9d9-9976616-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-b649c93692b4c9d9-9976616-0
  • 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
7551eb0b6dee2bad94cc0e52f85d5dffb46a02b5fe5421b6496a3b662cda9944		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8265 bytes

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