明确的dot.net单点登录解决方案 - 开发，窃取还是购买？

The problem: We have several dozen one off applications in our environment scattered across a dozen servers. Some apps are secured with one-off form/db based logins. Some apps have permissions defined in web.config. Some apps have folder level NTFS permissions set (some with domain user accounts, some with local user accounts for external users). Needless to say, this is an absolute mess. The problem: We have several dozen one off appl