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

Static analysis result for SHA-256 66b86a26a9e06a4b…

MALICIOUS

Office (OLE) / .XLS

127.0 KB Created: 2020-11-20 17:59:00 Authoring application: Microsoft Excel
MD5: e4fa872c1a6f8a1876b5e499c46f5945 SHA-1: ed566878dcca166873e9e62d5c98a6103ba22ac1 SHA-256: 66b86a26a9e06a4b74ef9a32031d5f27aaf5151f4fb7880d66b654b4149cdd0e
148 Risk Score

Malware Insights

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

The file contains critical Excel 4.0 macro heuristics, including an Auto_Open defined name and the use of dangerous formula APIs like RUN. The extracted XLM macro script shows evidence of attempting to construct a command to execute a new object using Net.WebClient, indicating it likely downloads and executes a second-stage payload. The VBA project appears to contain no executable statements.

Heuristics 4

  • 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.
  • VBA project contains no executable statements low OLE_VBA_MACROS
    Document contains a VBA project, but extracted modules only contain attributes/options/comments and no executable statements.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
ad10e8a75146b6007ff02b1d527ad9f0ba0364fddb999f35b506a847054f5db1		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 2432 bytes
macros.bas
fed365d3401536fb63e11d0a36cc7c35338c0a8c74a96fb254c46366ad6287cd		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 642 bytes

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