Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 91a0bf6df985e24d…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:40:29 Authoring application: Microsoft Excel
MD5: d23e9f1ff0b75dc65430e1a22dd7ef89 SHA-1: f78c78fcc2e902863dd50092c32051f366b93d9e SHA-256: 91a0bf6df985e24d07c2274a528ad459c837315eeaf6a04fddafa2fcca494942
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled workbook. Static analysis identified an Auto_Open defined name, indicating that the macro sheet will execute automatically upon opening. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary code, likely leading to the download and execution of a second-stage payload.

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
b72f6bd8a9d5e1c2a4f35666f627e276c2b2997af8ab576b72da5dacfbc9729f		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6493 bytes

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