Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 584b47ac1155cc73…

MALICIOUS

Office (OLE) / .XLS

142.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-03-25
MD5: eaebc39a26999b08698cada0e0c2f18c SHA-1: bbea900a65f330f3afff055c84823eda3b8d07e0 SHA-256: 584b47ac1155cc73ea15db59bbb145ccc87c737f19d93c9200cf0aefb5ac413d
200 Risk Score

Malware Insights

Emotet · confidence 95%

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

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a critical indicator of malicious intent. The macro uses the RUN function, a dangerous API, to execute a command. This command appears to construct a path to 'regsvr32.exe' and likely uses it to download and execute a second-stage payload from one of the provided URLs. ClamAV also detected this as Emotet, a known downloader family.

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-adc2d23d2dc26dd0-9950240-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-adc2d23d2dc26dd0-9950240-0
  • 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
eee0a3dec225fd0088c74c7ab34b064dd06b0d4f7198f4d9a113e7b902ce722a
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6706 bytes