Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 309d9d1c0d5bd696…

MALICIOUS

Office (OLE) / .XLS

95.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-07-13
MD5: 27374245ad09a0848498259da9b8d280 SHA-1: 892483f9df89808ebef78d3f6326301db3d477fd SHA-256: 309d9d1c0d5bd6964f0e28a4b22e0dbe0aafd97a13700afddb288be2a2a81b4c
200 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Service Execution: Service Execution T1566.001 Phishing: Spearphishing Attachment

The sample contains Excel 4.0 macros, specifically an Auto_Open function that utilizes dangerous formula APIs like RUN. This is a strong indicator of a downloader, and ClamAV detection confirms it as Emotet. The macro's purpose is to execute a secondary payload, consistent with Emotet's typical behavior.

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
85773188e79d904ef8ecf815a27f3a8200cc87e1822ab4901cc9bed29c53e636
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8156 bytes