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

Static analysis result for SHA-256 b5e1e66152fce112…

MALICIOUS

Office (OLE) / .XLS

36.5 KB Created: 2020-11-25 10:40:47 Authoring application: Microsoft Excel First seen: 2022-04-27
MD5: cbfa58c1c45149cf965339e5645e6f47 SHA-1: 72df1b96387b17ede774d0daaf205bfffb1bbde3 SHA-256: b5e1e66152fce112f26e600c07c5d6b280f78a071b5752836ada4c0f9dfdc72b
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1059.003 Windows Command Shell

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. The presence of dangerous formula APIs like RUN indicates that the macro is designed to execute arbitrary commands. The extensive obfuscated strings in the document body suggest an attempt to hide malicious content or functionality.

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
3dd8b7288b0348629ca9c410d7ce249bbc20732e4c563e51df9bcfd7d2e65071		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6478 bytes

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