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

Static analysis result for SHA-256 42af9724562b3bd6…

MALICIOUS

Office (OLE) / .XLS

44.5 KB Created: 2020-11-05 12:02:59 Authoring application: Microsoft Excel
MD5: ccfa95ae24dd8cf846f589132976dc18 SHA-1: 250cc23c92659fa8c257168dd6d00c34e62ed658 SHA-256: 42af9724562b3bd690ae30dbc6c1b99abb39e50adbb41f777feb9bceb3f3c102
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell

The sample is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open function, which is a common method for executing malicious code upon opening the document. The 'RUN' function is explicitly identified as a dangerous API call within the XLM macro, suggesting it is used to execute arbitrary commands. 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
44ae9fada74fa8ba4fc899f59f8e4016be39d461636f0c0f4c87380a165ada7b
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 13406 bytes