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

Static analysis result for SHA-256 e1a372f8369e50d1…

MALICIOUS

Office (OLE) / .XLS

41.5 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 5b2a870dd64945d40cff020ac3fae013 SHA-1: 43aaf0bfdf548e3405f748f9231ffa830d8da72c SHA-256: e1a372f8369e50d159adcf855df63ea64389be97af0bdfe7281539a6897f5604
140 Risk Score

Malware Insights

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

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 itself contains references to dangerous formula APIs, specifically the 'RUN' function, suggesting it is designed to execute external commands or payloads. No specific family could be identified, but the technique is consistent with macro-based malware delivery.

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
93a4ec0e5500d72b2a48cecdf10888cbc17bf7f7d49251072fd1d1a312c2aafb
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8017 bytes