Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 9b08eaf2495dde7b…

MALICIOUS

Office (OLE) / .XLS

60.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-10
MD5: 4521a64f9f2102885f8b84f0737c0b94 SHA-1: b91adcc7f622092fa155f3db1bc374f51b1c62bb SHA-256: 9b08eaf2495dde7bba59dfc874ef32bc7df37105cd26e83b131dad62b42ccc4c
200 Risk Score

Malware Insights

Emotet · confidence 95%

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

The sample is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro that utilizes dangerous functions, specifically the RUN function, to execute external code. The macro sheet contains multiple URLs which are likely used to download and execute a second-stage payload. ClamAV detection further confirms this is Emotet.

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-ea85817e7e81383e-9951566-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-ea85817e7e81383e-9951566-0
  • 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
a2d033763c15494b12e31c971331fca1f0f387966c5e482c3931d5611c30d5d1
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8260 bytes