Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 6591e1f9dcb34500…

MALICIOUS

Office (OLE) / .XLS

63.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-16
MD5: e37da0df2ed695f67375beb8e730ab8c SHA-1: f8dbf467aad542eb726204c23754599107952ad8 SHA-256: 6591e1f9dcb3450001b5217e396746867c361a423ca5666f756a92066f1b7339
200 Risk Score

Malware Insights

Emotet · confidence 95%

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

The file is an Excel 4.0 macro-enabled workbook containing an Auto_Open macro. This macro is designed to execute a series of concatenated strings that form URLs, which likely host a second-stage payload. The ClamAV detection and the presence of dangerous formula APIs in the XLM macro confirm its malicious nature and point towards 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-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
81a890043a2bf9bada66e5f829f683706b013cf3d1f82e11ea536e934629d60f
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8316 bytes