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

Static analysis result for SHA-256 9df9411d2ef91e22…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:47:21 Authoring application: Microsoft Excel
MD5: 5eb4f8981b19fd69ee49d466f35833d8 SHA-1: 8e32b80578d9f2ed1f72966ade5960cc7e367517 SHA-256: 9df9411d2ef91e220ad822058474301eeba457026e2c79eb099eddd5a64ec42e
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1059.001 PowerShell

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. This indicates the workbook is configured to automatically execute a macro upon opening. The presence of dangerous formula APIs like RUN further confirms the intent to execute arbitrary code. While no specific URLs or hashes were extracted, the Auto_Open functionality is a strong indicator of malicious intent, likely to download and execute a secondary 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
9d55139bbfedf1f18de8fdcff295da95a9082b2fa1ff1fba12299dbe9b6b50ef
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6466 bytes