Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 5edfa18d54052256…

MALICIOUS

Office (OLE) / .XLSX

128.2 KB Created: 2022-01-17 21:27:03 Authoring application: Microsoft Excel
MD5: fdb7bbd84b02f12d788fb8a22184de04 SHA-1: 3ef00ce2534a4b6d5317f41d52ba2493d0ae1ab5 SHA-256: 5edfa18d54052256d62cd14523eee828be94dbd74b83296ece55b13122e94c56
140 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a critical finding. The macro attempts to execute a command to download a payload from the URL 'http://0xc12a24f5/cc.html'. ClamAV also detected this as Emotet, a known downloader family. The macro's intent is to download and execute a second-stage payload, aligning with Emotet's typical behavior.

Heuristics 3

  • 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.
  • ClamAV: Doc.Downloader.EmotetExcel01220-9936774-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.EmotetExcel01220-9936774-0
  • 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
a0fd1b709c0182b7bfad87bd5382ad41592e9af0d0093f5e68d1ff145f18d235
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 653 bytes