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

Static analysis result for SHA-256 4870c4ba7a1d2b94…

MALICIOUS

Office (OLE) / .XLS

41.5 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: ed976d3a965cb5d52e0d47ea4a4594c0 SHA-1: c00de4b68a6189541c028d491ff34d896f637b70 SHA-256: 4870c4ba7a1d2b949ab744cb459e2edac8f65d9535dca1591d2eb93383c20def
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1059.001 Command and Scripting Interpreter: PowerShell T1059.003 Command and Scripting Interpreter: Windows Command Shell

The file is an Excel 4.0 macro-enabled spreadsheet. Critical heuristics indicate the presence of an Auto_Open macro and the use of dangerous formula APIs, specifically the RUN function. This suggests the macro is designed to execute arbitrary commands or download and run a second-stage payload. No specific family could be identified, but the technique is common for initial access.

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
e2b5636407d327fbb0e9d15430dedfbe4d4ff958ed88ce5e4a01292038cd3932
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7923 bytes