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

Static analysis result for SHA-256 2f2d254fe3758b41…

MALICIOUS

Office (OLE) / .XLS

56.5 KB Created: 2020-12-01 09:04:03 Authoring application: Microsoft Excel
MD5: aebc4a81e35c241ad30f4617f8392729 SHA-1: be6027a68592e5ea08cff4b0153164a87f689f0a SHA-256: 2f2d254fe3758b4119f09c4be7b8eba4a041cb469d4331d255ce62e074e1e324
100 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1059.001 PowerShell

The critical heuristic OLE_VBA_ACTIVEX_XLM_CELL_STAGER indicates that VBA code is used to execute obfuscated XLM formulas. The VBA macro 'documentoformato' reconstructs and executes XLM formulas, and the 'enel_Layout' subroutine triggers this process. The reconstructed XLM formula likely serves as a stager to download and execute a secondary payload, although the specific URL or execution command is not directly extractable from the provided evidence. The presence of both VBA and XLM macros points to a complex execution chain.

Heuristics 3

  • VBA ActiveX event runs worksheet-decoded XLM formulas critical OLE_VBA_ACTIVEX_XLM_CELL_STAGER
    VBA code attached to an ActiveX/UserForm event reconstructs formula text from worksheet constants using Split/Replace/Mid or character shifting, then executes it through ExecuteExcel4Macro or Run. This is a high-confidence malware stager that hides XLM formula execution in sheet cells; it is not a document-parser CVE.
  • 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 macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
18fb921acb44c0adeab3c6e768f9b1946c5372600eef0bc1350939fe5bcd3fd0
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 458 bytes
macros.bas
5dd215fa73876d143c49f14bb905c325ce4aa0aa60dc061e6af5fce461854156
vba-macro oletools.olevba.extract_macros (decoded VBA source) 1450 bytes