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

Static analysis result for SHA-256 78418e330556118a…

MALICIOUS

Office (OLE) / .XLSX

35.5 KB Created: 2020-11-27 11:46:37 Authoring application: Microsoft Excel
MD5: 0c81eca061337d73c4e12f30d197af03 SHA-1: c5cfb8535b23a2735fee2d5cc8c91e1170539ead SHA-256: 78418e330556118a3bccf855032aedbf21caf6a5053716a39ecd475de80a9175
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding indicating automatic execution upon opening. The presence of dangerous formula APIs like RUN further confirms the intent to execute arbitrary commands. This points to a macro-based execution attack, likely for delivering a secondary 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
18ce3ffbf25edc65d98f9e6ff9258b71e385f01f373676d46fdecc07068a99af		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6701 bytes

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