Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 10cb7ced7eb0f24b…

MALICIOUS

Office (OLE) / .XLS

114.5 KB Created: 2022-01-24 01:40:11 Authoring application: Microsoft Excel
MD5: 61033b6d9b7e0d6710d903c463d06876 SHA-1: 91b25cce6d4a8d469508520b67d85e49ecadac60 SHA-256: 10cb7ced7eb0f24bceedf42355377a531bc2052eb2e2e136149fee9e41595b4a
200 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file is an Excel 4.0 macro-enabled spreadsheet containing an Auto_Open entry, which is a known technique for executing malicious code upon opening. ClamAV identified the file as Xls.Downloader.Emotet, indicating its role as a downloader for the Emotet banking trojan. The macro uses dangerous formula APIs, including the RUN function, to execute the payload.

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-bd646319c2d29cd6-9951195-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-bd646319c2d29cd6-9951195-0
  • 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
86637063ac2c97bbefdbc9033f21cd30e9484ed274aba63ad50d62dfa1de93cd
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 4341 bytes