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

Static analysis result for SHA-256 c642ac635bf97673…

MALICIOUS

Office (OLE) / .XLS

425.0 KB Created: 2021-12-16 12:50:02 Authoring application: Microsoft Excel
MD5: 856ae482985608c94e524dc3e41ca277 SHA-1: b5d6424015557a567574d550d1aac4eff99f75e3 SHA-256: c642ac635bf976732ffcbce421b8f60a6a47428d5edeaaf05496509ccef6f34f
60 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 heuristic. The presence of an OLE_XLM_AUTOOPEN heuristic suggests that the macro is designed to execute automatically upon opening the spreadsheet. The document body is heavily obfuscated and truncated, preventing a detailed analysis of its specific content or intent. However, the combination of an encrypted macro sheet and an auto-execute heuristic strongly suggests a malicious intent, likely for downloading and executing a secondary payload.

Heuristics 2

  • 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.
  • 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.