Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c640371b8654bb79…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:36:46 Authoring application: Microsoft Excel
MD5: 6830da0b003cb0f40ac40a8fb2780e4d SHA-1: 0eadd1ba157beb9b2f416f5a48ec3debade7e0e9 SHA-256: c640371b8654bb7954f7a2ea7cb1903f23f53156bd514b48a44ac2185cac7318
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 sheet that contains an Auto_Open defined name, indicating it will execute automatically when the workbook is opened. The heuristics indicate the use of dangerous formula APIs, specifically the RUN function, which allows for the execution of arbitrary commands. This suggests the file is designed to deliver and execute a malicious payload.

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
4955751da1cb1f053c4331eb04d81e69a8b6518fda664b794eb2cea966af7755		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6642 bytes

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