AEM does maintain JCRSession which i not implicit but can be accessed from ResourceResolverFactory object as mentioned above (slingRequest.getResourceResolver().adaptTo(Session.class)) and you can do all the operation that you expect from HttpSession. But if you are really interested in HttpSession then you can get it from slingRequest object as it has extended the httpserveletrequest (slingRequest.getSession(true/false)).
Let me know if you need more detail