Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 644afc34a416b142…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:25:21 Authoring application: Microsoft Excel
MD5: 7e4d4f45217cc35a41acfa9d3995fa42 SHA-1: 647ae867a6bddc047fe289e08b848405124e6fbb SHA-256: 644afc34a416b142b9d1113687dd9c56b780052b62ca4015717dc7f988589e23
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file is an Excel 4.0 macro-enabled workbook containing an Auto_Open defined name, which is a common technique for executing malicious code upon opening. The critical heuristic firings indicate the presence of dangerous formula APIs, specifically the RUN function, suggesting the macro is designed to execute arbitrary commands. This points to a downloader or initial execution stage for a more complex attack.

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
cab0067a367a45b7202d2ef0fe2fcf08ccc245879553fbfbd8e2fa5aa545148e
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6439 bytes