Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 5ca55bbe117677a9…

MALICIOUS

Office (OLE) / .XLS

91.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-11-11
MD5: cc0c79cb35af7a2896397178af6f35fb SHA-1: 5a89d2b3e6e2faad418663c84cff33adaddc7540 SHA-256: 5ca55bbe117677a9855a4bc8615c70eb7d4d0acf3ba863ed8919afc42547d847
200 Risk Score

Malware Insights

Emotet · confidence 95%

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

The file is identified as malicious by ClamAV with the signature Xls.Downloader.Emotet-ca2435d8af069a3f-9977227-0. Static analysis revealed the presence of Excel 4.0 macros, specifically an Auto_Open defined name that utilizes dangerous formula APIs like RUN. This indicates the macro is designed to automatically execute a payload upon opening the spreadsheet, consistent with downloader behavior.

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-ca2435d8af069a3f-9977227-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-ca2435d8af069a3f-9977227-0
  • 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
5a5bc579f763935a1a68145bb71bbc083fe12eaeeb5991041e4c5b202ccb4a4f		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8355 bytes

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