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

Static analysis result for SHA-256 00aadd0cee3b536e…

MALICIOUS

Office (OLE) / .XLS

43.0 KB Created: 2020-10-16 11:38:24 Authoring application: Microsoft Excel
MD5: 81104359dc0ad88009ac9334785c5577 SHA-1: 0511f33e537f8e457e64a628703756cf1e828b65 SHA-256: 00aadd0cee3b536e77552dad33c846dc9abec9578a2058a686b0d1cb70f979f2
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The critical heuristic OLE_XLM_DANGEROUS_FN indicates the presence of dangerous formula APIs within an Excel 4.0 macro sheet, specifically the RUN function. The Auto_Open defined name further confirms that this macro is set to execute automatically upon opening the workbook. This suggests the file is designed to download and execute a secondary payload.

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
b1689a3f06876890f1cc65e2e1f8f2b02f950ad6bd16552bbf527667da847e7f		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 9250 bytes

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