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

Static analysis result for SHA-256 9b81510696a3940f…

MALICIOUS

Office (OLE) / .XLS

36.0 KB Created: 2021-02-16 17:06:00 Authoring application: Microsoft Excel
MD5: 9dae84e59f3eb2967f204213a0392745 SHA-1: 9bf4782d59bc708c34eb2747a889b0c8c32b0304 SHA-256: 9b81510696a3940f9b26d1151d8d4a137dab07df25d5e520453d95c02dc36a2d
80 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications

The file is an Excel 4.0 macro-enabled workbook. Heuristics indicate the presence of an Auto_Open defined name, which is a common technique for executing malicious code when the workbook is opened. The macro sheet contains obfuscated formulas and string concatenations that likely lead to code execution, but the exact payload could not be determined from the provided evidence. No specific family could be identified.

Heuristics 2

  • 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.
  • 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
1f93dc0b0da0ad887d8c208cab9a4e4b6eceb089bf41761fa6abc16ef7aa0cb5
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 16325 bytes