The recent versions of PowerShell have had a serious investment in security. PowerShell employs several technologies to ensure that it is the most secure shell on Windows. Some of these technologies are execution policies, constrained language mode, Just-Enough-Administration, script logging, and Anti-Malware Scanner Interface integration.
That said, PowerShell has an extensive red team community that employs various techniques to take advantage of its integration with .NET and the fact that it is installed on most recent versions of Windows. Check out some of the security modules on our list of the top 50 modules.