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

Static analysis result for SHA-256 3741beebd0cc99d5…

MALICIOUS

Office (OLE) / .XLSX

36.5 KB Created: 2020-11-25 10:44:29 Authoring application: Microsoft Excel
MD5: 7100b18f5a7563896d1f6e5ae207ffcd SHA-1: 3499c7026993f39a079d82e8542e7edc23f11c7d SHA-256: 3741beebd0cc99d5c36f9dde9d870cd97658026aa52da34991738267093b6016
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1059.003 Windows Command Shell

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. The macros utilize dangerous formula APIs, including the 'RUN' function, indicating an attempt to execute arbitrary commands. This suggests the file is designed to deliver a malicious payload or perform unauthorized actions upon opening.

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
1a5aa144962847cd15f2366b7122a66cc854327cea524a1e77bd4451c4731e57		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6561 bytes

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