Malicious Office (OLE) / .XLS — malware analysis report

Static analysis result for SHA-256 48ea8d8723a8ba15…

MALICIOUS

Office (OLE) / .XLS

36.0 KB Created: 2020-11-25 10:45:20 Authoring application: Microsoft Excel First seen: 2022-02-19
MD5: 7e5c7c22612a274de6e5a671d59338c5 SHA-1: bd0d147cadad8e36ffb5581477e733f7a44014d5 SHA-256: 48ea8d8723a8ba151a6d6f6bc1b43ab25f018fea7a03acc00aec77a19b844038
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1059.003 Windows Command Shell

The file is an Excel 4.0 macro-enabled spreadsheet. Static analysis detected an Auto_Open defined name, which is a critical indicator of malicious intent. The Auto_Open macro is configured to execute dangerous formula APIs, specifically the RUN function, indicating it is designed to launch arbitrary commands. The presence of the Auto_Open function and the use of the RUN command are the primary indicators of this attack pattern.

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.
  • 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.
  • 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
8f1722fa26ef9b7d4a5a29b5bfc8b79f47787e1e7b48ecb38235782a46fb0575		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6618 bytes

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