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

Static analysis result for SHA-256 42c6d134e3cda796…

MALICIOUS

Office (OLE) / .XLSX

132.5 KB Created: 2012-01-04 06:53:00 Authoring application: Microsoft Excel
MD5: 8e81cc3322202aba7c7774bc9a5cab96 SHA-1: f612ec8442e649078c1c95593261b85ae0b86166 SHA-256: 42c6d134e3cda7967b7ffbe6f58678cb8b1ec3f3cd23290b3b431fc9d4b2ff72
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1059.001 PowerShell

The sample is an Excel file containing Excel 4.0 (XLM) macros, specifically an Auto_Open macro. This macro is designed to execute automatically when the workbook is opened. The presence of dangerous formula APIs like RUN indicates the macro is intended to perform malicious actions, such as downloading and executing a second-stage payload. The document body text, though heavily obfuscated, suggests protection mechanisms are in place, further supporting a 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
68d147bb05716d2e7f50be4dc93d112e5a1f3433983b13f5d4c58454e71b3fb5		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 69873 bytes

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