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

Static analysis result for SHA-256 11aeb722a56daa3a…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-27 11:45:12 Authoring application: Microsoft Excel
MD5: f49c11733ab780c97ada955dbd9a53f3 SHA-1: 3c8a22ee1678be937e583050be9128a8f9a4126b SHA-256: 11aeb722a56daa3a4dfeaf1804684dd6d743cc1a1b06897f5477b032c073ac4f
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 function, which is a known method for executing malicious code within older Excel versions. The presence of dangerous formula APIs in the Auto_Open macro indicates a high likelihood of malicious intent, likely to download and execute 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
66642d3fc58c0cb74553d133735383c5329a0aab68442a28d6ea130d24c7e871		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6782 bytes

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