Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 cd16c800c3103df7…

MALICIOUS

Office (OLE) / .XLSX

60.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-17
MD5: 4853d394a035151ecccc83b8326d2f88 SHA-1: 8808627598d0217e40962072b87f5dcc8eb64f92 SHA-256: cd16c800c3103df71e2b216b499d25365f1d746bce424b86f99bf3fbe583c504
200 Risk Score

Malware Insights

Emotet · confidence 95%

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

The sample contains Excel 4.0 macros, specifically an Auto_Open function that utilizes dangerous APIs like RUN. This indicates an attempt to automatically execute code upon opening the document. The extracted URLs are highly suspicious and likely serve as download locations for a secondary payload. ClamAV detection further confirms its malicious nature, identifying it as an Emotet downloader.

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
c9424d8896eee7de77a94a4b79caaaa3c6ad54074296d7a874abf2efc9d6f719
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8352 bytes