Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 9707bd249682a058…

MALICIOUS

Office (OLE) / .XLS

80.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-16
MD5: fccaf86bf1acda44d1707c32785b4eb7 SHA-1: 510bd31bf30c69016db58af4a99b7eaecf401685 SHA-256: 9707bd249682a0580aa9d7b04959363691210f2cde1cdd80862eb581dc12a179
200 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: User Execution: Malicious File

The sample is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro that uses dangerous functions, specifically the RUN function, to execute code. The macro attempts to download a second-stage payload from multiple URLs, including 'http://byrndest3.com/cgi-bi/TEq/'. This behavior is characteristic of Emotet downloaders.

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
2fdf21f2db447f9be93416b81af1c740576c18d6efe5c8c6f3d215a65c941f1d
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6790 bytes