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

Static analysis result for SHA-256 ffe1187bdacccc49…

MALICIOUS

Office (OLE) / .XLS

153.0 KB Created: 2020-04-23 12:26:24 Authoring application: Microsoft Excel
MD5: 25ee3ffa6aa2ba05b8119a3c5417814f SHA-1: 0e5572cf3d3dbfb0650f24abed83d8e1b6c2d8c0 SHA-256: ffe1187bdacccc4933d4b3e8aa2eebc38222256f7c0aae537f9f3c0786ce0ba3
100 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications

The sample is an encrypted Excel 4.0 macro sheet, indicated by the OLE_XLM_ENCRYPTED_MACROSHEET and OLE_XLM_AUTOOPEN heuristics. The document body is heavily obfuscated and truncated, preventing a clear understanding of its purpose. However, the presence of encrypted macros strongly suggests malicious intent, likely to download and execute a secondary payload.

Heuristics 3

  • Encrypted Excel 4.0 macro sheet high OLE_XLM_ENCRYPTED_MACROSHEET
    Workbook contains an Excel 4.0 macro sheet and BIFF FILEPASS encryption. Password-protected XLM macro sheets, especially the default Excel password path, are a common malware evasion pattern because static formula extraction may fail until the workbook is decrypted.
  • OLE metadata lists many Excel 4.0 macro sheets high OLE_XLM_DOCPROPS_MACROSHEET_INVENTORY
    Workbook contains a BIFF Excel 4.0 macro-sheet marker and its clear OLE DocumentSummaryInformation stream lists many MacroN sheet titles. This is a useful static signal when FILEPASS encryption prevents formula extraction from the workbook stream.
  • 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.