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

Static analysis result for SHA-256 453140c62a2afa74…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:36:10 Authoring application: Microsoft Excel
MD5: 457d3e4e1c3b4602607a1e1f44c5fd51 SHA-1: 4182ffd7b3f6d4ca1685349c6b782cd06ab679da SHA-256: 453140c62a2afa743452c16c21bb79fec2574ecc6aec11f3ce9811e0c9dc2c48
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. This indicates that the macro will execute automatically when the workbook is opened. The presence of the RUN function within the macro sheet is a strong indicator of arbitrary code execution. The document body contains obfuscated text, likely intended to evade detection or to be part of a lure, but the primary malicious functionality is driven by the XLM macro.

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
389c646c7ab227087a89b470a844a2ce03a528bfbeff965903a08a797b8dff34
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6445 bytes