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

Static analysis result for SHA-256 73f8ff85967342f9…

MALICIOUS

Office (OLE) / .XLS

73.0 KB Created: 2020-05-20 08:20:55 Authoring application: Microsoft Excel
MD5: 2391a10550ac36c64a4a0175e46cc32f SHA-1: c73c6b51a055197bdd9cabd03d04d87b345aca84 SHA-256: 73f8ff85967342f9ebd77cbf45174a9233c0b265b479ed3293ab453609be124f
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a critical finding. The macro is designed to execute dangerous functions, including the RUN function, indicating it attempts to download and execute a second-stage payload from the reconstructed URL http://os.meduarncbx.com/DGvqBLj. This points to a macro-based downloader attack pattern.

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
734027e1dd43b08f7ac2881a598dccfff5aec8f3d91d44417d4acfc5286d810f		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 39850 bytes

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