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

Static analysis result for SHA-256 285d72443d3d291c…

MALICIOUS

Office (OLE) / .XLS

41.0 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 6745b6d08563676672f85f1cf2a8a58e SHA-1: db9bc434bbdb0dd17225a91f9591108498bfdcc4 SHA-256: 285d72443d3d291caffb91b4c4c853009a19448c3c89d8be4af6bb33043ecc5a
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample is an Excel file containing Excel 4.0 (XLM) macros. The critical heuristics indicate the presence of an Auto_Open macro, which is a common technique for executing malicious code automatically when the workbook is opened. The macro sheet contains references to dangerous formula APIs, specifically 'RUN', suggesting it is designed to execute external commands or payloads. No specific family could be identified, but the technique is indicative of a downloader or initial execution stage.

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
2ed6663b0a4f217e1d378f5b5c3cc5cf01cbfda824db799d25bd73b050915f9a
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7931 bytes