Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 3b90ed51d34cbe21…

MALICIOUS

Office (OLE) / .XLSX

142.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-03-24
MD5: 697f10761d1b28be488c23d19b21e6cc SHA-1: 567deabfdda8ae9efeb08a8289b6564701540100 SHA-256: 3b90ed51d34cbe214a4a4c281203ade4645e1753e523624d6fe6d4c8a9a2f672
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 function, which is a known technique for executing malicious code. The macro uses the RUN function to execute a command that appears to construct a path to a second-stage executable. The ClamAV detection explicitly names Emotet, and the URLs extracted are consistent with Emotet's typical distribution infrastructure. The macro's intent is to download and execute a payload from one of the provided URLs.

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