Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 b3920ede40455fca…

MALICIOUS

Office (OLE) / .XLS

94.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-29
MD5: 120b24a43b5c01360440a62e99f5c162 SHA-1: ff2cfa2b10ab631064a1a108fe84a4eb3770451f SHA-256: b3920ede40455fca2fbb1edfc6299d2491fded7fa6e7fddb4a1fd4f74bfda921
200 Risk Score

Malware Insights

Emotet · confidence 95%

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

The sample is an Excel 4.0 spreadsheet containing an Auto_Open macro, identified by critical heuristics and ClamAV detection as Emotet. The Auto_Open macro utilizes dangerous functions like RUN, indicating it's designed to download and execute a secondary payload. The presence of the Auto_Open entry and the use of the RUN function are strong indicators of 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-ea81817e7f807ab1-9952142-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-ea81817e7f807ab1-9952142-0
  • 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
709f648888ea73fd84d73069053983f59de0087fb650fa2050897e85b5ddffd2
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8122 bytes