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

Static analysis result for SHA-256 fb7a6035b4d3bb4f…

MALICIOUS

Office (OLE) / .XLS

42.5 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 8a60030cd8aba0e7fc74396bc7b686ea SHA-1: 75586f090ad77b17c908632a9f2032e50d9256d9 SHA-256: fb7a6035b4d3bb4f80948799ccdc971f64243da8d3be21af368f474121837b4e
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1569.002 ShellExecute

The critical heuristic OLE_XLM_DANGEROUS_FN indicates the presence of dangerous formula APIs within an Excel 4.0 Auto_Open macro, specifically the 'RUN' function. This strongly suggests the macro is designed to execute arbitrary commands upon opening the spreadsheet. While the exact command or payload is not directly visible due to truncation, the presence of an Auto_Open function is a common technique for initial execution of malicious code. The document body contains heavily obfuscated and non-sensical text, providing no clear user-facing lure.

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
ae7db0701628dff029c01935f26045847d58fd0f879890801ae232e30871a0a1
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 9027 bytes