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

Static analysis result for SHA-256 e3ae198d091bb705…

MALICIOUS

Office (OLE) / .XLSX

36.5 KB Created: 2020-11-27 11:41:16 Authoring application: Microsoft Excel
MD5: 1ecce9c2ee8fbd5e700e1b32bcdc2ca5 SHA-1: 85405452c408a1f7b4aa8988afb5b4b0bf94cdff SHA-256: e3ae198d091bb70510d9ae9405c85f3a7f567ea7566f7d6cf063e056079e8607
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. This indicates the workbook is designed to automatically execute a macro upon opening. The presence of dangerous formula APIs like 'RUN' further suggests the macro is intended to execute arbitrary commands. While the specific payload is not detailed in the extracted scripts, the Auto_Open functionality is a common technique for initial execution in macro-based attacks.

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
0d3500291d4b50bb3912aaf5df486532b5225819b0507064b074efbb5b039581		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6814 bytes

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