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

Static analysis result for SHA-256 6d3835fb04b5ac6d…

MALICIOUS

Office (OLE) / .XLS

263.0 KB Created: 2020-06-18 11:28:06 Authoring application: Microsoft Excel
MD5: 93b262ba17d67869e7284fc5c81120ca SHA-1: 55c8a75b27dd966dfb5e533a01679f8fb47a2094 SHA-256: 6d3835fb04b5ac6df349b5d58f02018d0f0e93fc16fde1fbedfa1ef2422dfa58
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open defined name, which is a known method for executing arbitrary commands upon opening the workbook. The macro sheet contains references to dangerous formula APIs, specifically the RUN function, suggesting it is designed to execute a payload. No specific family could be identified, but the technique is consistent with macro-based malware.

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
1648dc20fbfe0bd415482782199842aa37b7fd845d650b535fe08b6bfae01849
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 58074 bytes