Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c3ba2b6e988c39ee…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:46:16 Authoring application: Microsoft Excel
MD5: a5a1cc89a1819544d3f95b246a11ac24 SHA-1: c82d30a9e45beb6351583c0d3973ebd38111671c SHA-256: c3ba2b6e988c39eeedf1c7375e48819de296d791a7f278486efc4176c17f74a0
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open defined name, which is a known technique for executing malicious code. The macro sheet contains a dangerous formula API, specifically 'RUN', suggesting it is designed to execute an external payload. The document body contains obfuscated text, further indicating malicious intent.

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
c1c808f9d8d9f4c5a7155cfa9e439a306e324c2692828102bce1867eeb417998		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6854 bytes

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