Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 58bdc8f73cba7b60…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:45:07 Authoring application: Microsoft Excel
MD5: e0e234ba6cd971204283a9142ad99a54 SHA-1: 761ec9b75c04dc158754e42d688993e8edf3267b SHA-256: 58bdc8f73cba7b601226f5db66d98f628d915352b4ea9336522fc106e0e1058c
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 upon opening. The heuristics indicate the use of dangerous formula APIs, specifically the RUN function, which is commonly used to execute arbitrary code. 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
347409b2ae2a58d2ba0b43f93844d87bbb501b41f877a69f6ea4714529f9b62e		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6448 bytes

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