I have an ASP.NET MVC application that authenticates users against Active Directory.
As I understand this is the process happens when a user logs on to his computer:
User enters credentials on the local machine.
Local machine checks if it already has an authentication ticket for these credentials.
If not, it contacts the first ADS server it can find that offers kerberos authentication functions
The ADS machine checks the credentials against the LDAP database.
If they check out, kerberos returns a TGT (ticket-granting-ticket) to the client machine
For a certain duration set in AD (usually 8~10 hours) this TGT will bypass any credential checking in case the local machine user wishes to connect to resources that require permissions not present in his bare user account (i.e. group memberships, additional machine and share access, etc.)
My question is how does IIS know about the TGT when the browser is making a request to it for my app? Does the operating system send it out on every outbound http request to every single website?
The server (IIS) will indicate to the client (browser) that it needs to authenticate by returning an HTTP 401 error code with a WWW-Authenticate header. The client detects this and determines if it can correctly authenticate. The way this works is as follows:
Determine who the requestor is by checking it's Service Principal Name. It exists as {type}/{fully.qualified.domain}, e.g. HTTP/resource.domain.com. This SPN is mapped to a machine or service account in AD. If this SPN isn't registered, the client falls back to a lesser protocol like NTLM.
Local machine uses the TGT to request a service ticket from AD. AD validates the TGT and looks up the SPN in the request and if found creates a service ticket encrypted against the password of the account associated to the SPN.
Client sends the service ticket to the server via Authorization: Negotiate YII... header.
Server decrypts the service ticket using the password it's been provided, either through a domain join, Windows Service Run As config, or keytab.
Server transforms the contents of the decrypted service ticket into a Windows identity.
Identity is presented to the application.
This flow isn't inherently web-specific. This is how all services authenticate themselves when using Kerberos.
Related
I am looking for some guidance on how I can use an Azure B2C custom policy to federate to a legacy Authentication Server. Here is the current flow that I would like to implement in the custom policy.
This protocol looks like a hybrid Oauth1 and the "actors" involved are:
Browser based user
Application Server
Authentication Server + protected resources
The Application server is preconfigured with an application id and an application secret provided by the Authentication Server. The Authentication server is also configured with a callback URL (pointing to the Application server). - Similar setup to OAuth.
Flow:
Step 1: The user requests a resource from the Application server by performing a GET on the application server (e.g. GET /resource
Step 2: The application server calculates an attribute using the preconfigured client secret and redirects the browser to the Authentication Server.
Step 3: If the Authentication Server determines that the user needs to be authenticated and may prompt the user for a username/password. This is transparent to the application server.
Step 4: The Authentication Server verifies the application server-provided attributes sent in Step 2 and responds by redirecting the user to the preconfigured application server callback URL. This request will additionally include a number of attributes set by the authentication server.
Step 5: The browser redirects the user to the application server’s callback URL and the application server uses the attributes received in Step 4 to calculate a resource request token
Step 6: The application server uses this request token to request protected resources and responds to the user's original request.
I am looking for ways to implement the above. Do I build this using a custom policy with an Oauth1 Technical profile Or an OIDC technical profile or something else?
The only way to do this is to create some middle layer than talks OpenId Connect to AAD B2C and talks the proprietary protocol to your legacy system.
Azure AD B2C can then make an open id connect request to your web server and it can do whatever it needs. Just have it respond back to B2C in an open id connect way.
I have setup my LDAP server with user details. I have setup my Ubuntu laptop to authenticate users from LDAP. The problem is, every time user tries to log in, Ubuntu tries to reach LDAP servers to authenticate. So when network connection is out, it shows authentication failed. What I want is when user logs in first time, Ubuntu authenticates from LDAP, and creates a local user profile, and stores credential somewhere on local. So when network connection is not available, it authenticates against last used credentials. And when system connects back to internet, it authenticates against LDAP.
Please help me with this. Let me know if any clarifications are required.
I have created LDAP Server, and my ubuntu system is already authenticating users against LDAP. I want to store the LDAP credentials to a local user once the user logs in for the first time, so that these credentials can be used for authentication when network connection unavailable.
If you are using SSSD as the LDAP client, enable its built-in credential caching. Take a look at options cache_credentials (for auth) and cache_first (for account information) in the sssd.conf(5) manual page.
If you are using nslcd as the LDAP client, install pam_ccreds for authentication caching and nscd for account information caching.
The main idea:
I have windows application (maybe IIS site, maybe standalone) that
natively accepts Kerberos authentication and impersonates user.
Kerberos token sent by client to app already has information about
user's groups SIDs, user's SID, etc.
On each request, from
HttpContext.Current.User I get information about user's groups'
SIDs, user SID, translate it to 'plaintext' and pass to non-windows
backend (as header, for example).
Backend (which can not do kerberos)
can read claims added by App from proxied request and send answer, which will be
passed to app and then to user (backend->app->user)
Well, what's wrong with this concept?
Why I can not find any existing apps that can work similar way?
The only thing I found is FASTCGI\CGI, which sets REMOTE_USER variable, but this is not enough - frontend had Kerberos with huge amount of data which is dropped by the way to backend.
I have problem integrating jFrog Artifactory with an Azure LDAPS.
Azure side is successfully configure, I get response by telnet on port 636.
Logs in the artifactory show this error:
Error connecting to the LDAP server:
org.springframework.security.authentication.AuthenticationServiceException:
User name.surname#bi****.de failed to authenticate
I understand that this error points to my user. But credentials for this user are 100% correct since I have enabled Azure Active Directory Services with user, enabled LDAPS and so on.
Can anyone specified in more detail what I was doing wrong on this picture below?
LDAP Integration screen
The search filter is incorrect, but the correct value will depend on what the users will log on with. If it's their AD username, you would use "sAMAccountName={0}" but the test ID you are using appears to be an e-mail address. To authenticate with your primary e-mail address, use "mail={0}" as the search filter.
Most likely "manager DN" / "manager password" needs a value as well. When you attempt to authenticate, the server connects to the LDAP service and binds with the "manager" account. It then searches for mail= and retrieves the fully qualified DN (FQDN) of the located object. The user supplied password is then validated by attempting to bind with the retrieved FQDN and user supplied password. If anonymous users have read access to the directory, you wouldn't need a manager dn/password. Anonymous read access is atypical for AD/Azure AD.
I use a "service" (i.e. non-user) account for my manager account -- using an actual user's account means someone has to come back and change the config every time the user updates their password. I set a long/complex password on service accounts and increase the password expiry time-frame so admins aren't re-configuring their applications monthly.
My understanding is that both JAAS and SQL Server can be configured to use kerberos in a domain environment, with an active directory server.
My understanding that JAAS gets the user credentials from the user or from a file at the time of the connection - asks the directory server for a ticket, and presents that to the server.
Where does the SQL Server Driver get its kerberos ticket from? (as it seems to be able to obtain creditentials from the users existing login). Does it get the user login ticket - or does it extract the credentials from the user's logged in session?
SQL Server Driver gets Kerberos tickets from TGT (ticket granting ticket). This TGT is a ticket that is part of user's logon session and can be used to get short lived tickets to authenticate to other services (E.g. SQL Server).
You can use "Kerbtrey" utility from Windows Server Resource kit to examine such tickets.
JAAS also uses the same tickets but it needs to be told to obtain tickets + configuration (E.g. name of Kerberos server) from file and that path is somewhat dependent on OS version.
SQL Server drivers uses Wind32 API to get tokens.