PHP和基于表单的.net身份验证之间的SSO

I'm not much familiar with .Net, but i have this situation. Our customer have few .net based web applications on one domain. These applications are using form-based authentication and sso based on this mechanism https://msdn.microsoft.com/en-us/library/dd577079.aspx . And my objective is to be able authenticate users in similar way from PHP application and also use SSO principles. I have example web.config file. Is there any simple way or way i will be able to implement? (all application are on same domain)

from web.config

<authentication mode="Forms">
                           <forms loginUrl="~/Login.aspx" defaultUrl="~/Default.aspx" cookieless="UseCookies"  name="cookiename" slidingExpiration="true" domain="domain.xxx"/>
            </authentication>

and membership part is:

     <membership> 
  <providers>
    <clear/>
    <add 
      applicationName="/"
      connectionStringName="TableAuthDB"          
      name="AspNetSqlMembershipProvider" 
      passwordCompatMode="Framework40"
      passwordFormat="Hashed"
      requiresUniqueEmail="false"          
      requiresQuestionAndAnswer="false"
      type="System.Web.Security.SqlMembershipProvider"
      maxInvalidPasswordAttempts="2147483647" 
    />
  </providers>    
</membership>

First I thougt about creating WS in .net which I could use for operation sign in and out a check if user is authenticated. But also with this step I'm not much familiar. Sorry for my english, hope it make sense at least a bit. And I'm absolute amateur in .net technologies.

Thanks for any help