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

Static analysis result for SHA-256 4a0dbc7d805a3cae…

MALICIOUS

Office (OLE) / .XLS

36.0 KB Created: 2020-11-27 11:41:20 Authoring application: Microsoft Excel
MD5: b35354685fa065827b045958fc829bae SHA-1: 6a913314a03d706f95c46b7e7bcf70f61d3cb553 SHA-256: 4a0dbc7d805a3cae171de8c58691411c4bb15c1d770d2ba8d8f2b9b867807513
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The file is an Excel 4.0 macro-enabled spreadsheet. Critical heuristics indicate the presence of an Auto_Open macro, which is a common technique for executing malicious code upon opening the document. The macro sheet contains a reference to the RUN function, suggesting it is designed to execute arbitrary commands.

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
86d451f5bf0d339de4de805a71292f72c5334a4fd5b3b4781b401e3ff2e783ef		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6658 bytes

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