Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 d6c1152b58e9824e…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:45:38 Authoring application: Microsoft Excel
MD5: b0398e7c21b496f5ffdb4072b8106b33 SHA-1: 502212ee9b160926894914a6c415a73850311efa SHA-256: d6c1152b58e9824e2297666f13e67bc0a8cf46dbd57ab7b94957dc8f287c7dc4
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 function. This function is designed to automatically execute when the workbook is opened, indicating a malicious intent to run arbitrary code. The critical heuristics indicate the use of dangerous formula APIs within the XLM macro, specifically referencing 'RUN=0', which strongly suggests the execution of an external payload. The document body contains obfuscated text, further supporting the malicious nature of the file.

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
7766fef68e6c5612a37762645227a72751eeccbd1dfbb93f5f4382dd6895d837
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6494 bytes