Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 233079d3b306cd4b…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:38:33 Authoring application: Microsoft Excel
MD5: 6764f7d9e405e2ef181b9aab88725a60 SHA-1: e885e9e83ade3b99f758f357add5a57670c477c1 SHA-256: 233079d3b306cd4b3956683c74198cf87fe7d8fe99d1ecf1c77f24eaf822b0a5
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 sheet that contains an Auto_Open defined name, indicating it will execute automatically when the workbook is opened. Heuristics indicate the use of dangerous formula APIs, specifically the RUN function, which is commonly used to execute arbitrary commands. This suggests the macro is designed to download and execute 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
8c6d7083e2856ab11927ce3c7611c77d3786bbdd5319867377ac205774adf50b		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6723 bytes

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