Oracle database authentication using kerberos and AD - oracle

We are in the planning phase of configuring our soon-to-be-upgraded databases (19c) to authenticate directly against AD (no oracle proxy). I have read a handful of documents from Oracle on how to do this. Most of the documentation focuses around using passwords (password filter/verifier). The only problem is that our AD administrators are dead-set against implementing Oracle's password filter into our existing AD infrastructure. That being said, one of the security guys said we could implement the oracle authentication using Kerberos instead. From what I have read, and the documents are scattered all over the place, and nothing that detailed, to use Kerberos:
1) The client no longer uses a username/password - they connect using a wallet-style connection (e.g. /#dbname)
2) Not only does the Oracle DB need some configuration changes, but so does every client that plans on using Kerberos
I don't know anything about Kerberos, how it works, and what goes on when you implement this, but I was hoping for, at the end of this is:
1) No client changes/installs (only the oracle DB would have config changes)
The user will continue to provide credentials as before - completely transparent
2) No need for the password filter as our admins have a "beef" against it
So my question is:
If using Kerberos directly against AD on >=18c:
1) Does the client user still provide a username and password to authenticate against AD, or does the client simply get "accepted" due to the tickets/tokens/configuration that occurs on the client (i.e. the client is simply trusted)?
2) Is there client config changes that need to occur, or does the client reach out to the DB and the DB, with its config changes, does all the legwork to authenticate against AD based off of client info being passed
3) Does any additional manual component need to occur on occasion (periodically retrieving a ticket/token/something) (because, say, it expires)
So in the end, we want to have complete transparency with every client and using something other than the password verifier with AD.
Thanks in advance.
-Jim

It sounds like you want to authenticate Windows clients against an Oracle database over a network using Active Directory without making any client changes.
This is pretty open-ended and complex StackOverflow question.
Probably you've been reading the docs about Third Party Network Authentication using Oracle Advanced Security. You can use Kerberos, SSL, RADIUS, PKI, etc. For most of these options, you need to do some setup on the client, because both the Oracle client and server need to authenticate or verify with the third-party system.
I think you need Enterprise User Security (using Oracle Internet Directory). Assuming you go with password-based authentication, you don't need client changes. In this scenario, Oracle Internet Directory can synchronize its user directory with AD, so your users can use their same username/password. However, when they change their AD password, they'll need to change their Oracle password separately.
On a different note, you may be able to alleviate your AD admins' fears about Oracle password complexity requirements, since you can change or remove those to fit your AD requirements.

Related

How to store a password for later use?

I need to be able to store a user's Exchange password so I can use it to perform some task later on, using EWS. I know storing passwords in plain text is a horrid crime, so what options do I have?
In my case, my application will have access to an administrative account that will have the ability to use impersonation to work with users' Calendars. I need to store the password of this admin account so I can use it while authenticating with the Exchange server at a later time. I am not planning on using the EWS Managed API.
I have a user that created a calendar app with similar requirements. By default, an account that has these permissions globally is horrible and not recommended. Impersonation roles were granted by department that required access to the app to reduce risk scope. However if you require this globally, here's what I recommended for mitigating the account/password exposure:
Restrict the accounts functionality to Exchange services only. Features like log on locally and other general domain user privileges are not needed for an EWS service account that only needs mailbox access and impersonation roles. In this case, the account cannot log onto a computer nor can it be used for RDP. This limits exposure for malicious use.
The user/pass can be stored in your applications database and the connection string would also be stored outside of your application, there's a lot here: https://security.stackexchange.com/questions/22817/how-to-encrypt-database-connection-credentials-on-a-web-server and encrypting the password within the database; further reading: http://www.darkreading.com/safely-storing-user-passwords-hashing-vs-encrypting/a/d-id/1269374
Restrict DB server and management access. This is a larger issue than it should be if the database server is shared between groups. Audit the database server access, and re-restrict if you have too many cooks in the kitchen. The database server should also not be directly accessed by user networks but that may be a larger issue to tackle.
Restrict access to the application. As in, is it available externally or only available inside your perimeter? Either way, the application should also include authentication just to access, using Kerberos or some other SSL auth, make sure the application cannot be used to DoS the EWS services from over-access.
Create a one-off throttling policy on Exchange for this user and assign accordingly to prevent the application from breaking EWS or limiting regular user functionalities. This is something Blackberry admins learned the hard way if they didn't follow recommendations. When BES server wouldn't properly tear down connections, web services would start dropping valid client requests. As such BES had to instruct users to create a one off throttling policy for various Exchange features. I did the same for the user that created my EWS app. And a few times it saved me.
Really it will boil down to good application design and coordinating requirements with the Exchange team.
Don't's:
Don't store the username/password in Apache/IIS pages or the connection string
Don't grant global permissions for the account if you don't have to
Don't allow unauthenticated access to the application and allow unlimited connection times
Hope this helps.

API to add principals to Kerberos

I am trying to kerberize my RESTful backend and I am not seeing anywhere in the GSS-API documentation how could I add a user/service - i.e., I understand the authentication process with GSS-API, but not the signup process. To make my question simpler : kinit is the command line tool used to add principals, is there an equivalent for GSS-API ? If the answer is no - should I go and look at the kinit source code and port it to my project (using system("kinit ...") raises security questions/problems so I am not thinking about using it) ?
Users should be added to the Kerberos database using API provided by Kerberos Distribution Centre. In Microsoft Active Directory, KDC uses LDAP as its database, so users can be added/removed using JNDI, as described here: http://cyberlizard.livejournal.com/120080.html.
kinit not a tool for adding users but for (simply speaking) "logging in", or (technically speaking) it's a tool that "obtains and caches an initial ticket-granting ticket for principal" (see: http://web.mit.edu/kerberos/krb5-devel/doc/user/user_commands/kinit.html), i.e. it takes credentials (i.e. for example principal and password, connects to KDC and tries to receive initial TGT from it. Client).

Securely transmit password information

I work as a student web developer for my computer science department and I've been asked to look into a modification of our password reset procedure for linux accounts. Currently users will log in with their university credentials (via Active Directory) and after being authenticated they get a temporary password through email which they are forced to change as soon as they log in. This way eben if the temporary password it intercepted there is a very short time span in which it could even be used.
Now the idea has been posed that instead of using a temporary password that we might allow the user to pick a new permanent password and set it directly through the web utility. It is my understanding that https is more of "the best we have" than "a great way to secure information". Are there any other avenues I can explore for securing the new password so that we can feel comfortable implementing such a system?
Basically, if you communicate with a server over HTTPS and the private key of the server isn't exposed to someone else, you can be sure that anything you transfer (e.g. the new password) can only be decrypted by the server. Additionally the server certificate assures, that the server you are communicating with, really is the server you want to communicate with.
So, using HTTPS provides authentication and prevents eavesdropping.
If you are working with Active Directory, it is my understanding that the Password Modify Extended Operation (which requires the existing password) is not supported. Therefore, the password must be changed with the LDAP modify request. One solution would be to use the UnboundID LDAP SDK with a web application to execute the LDAP modify with the new password. The modify request should be transmitted over a secure connection, or a non-secure connection promoted to a secure connection using the StartTLS extended operation.
see also
AD password change
Using ldapmodify - this article is about the command line utility ldapmodify but the concepts are useful.

Using LDAP authentication with liquibase

Is it possible to use LDAP authentication with Liquibase?
If not, how have others solved the problem of automating changes to production database schemas using Liquibase (yet still keeping the database credentials secure)?
LDAP is used for server-side authentication. Not all databases support it, for example MySQL only supports it in it's Enterprise version.
Securing the credentials, used by clients like liquibase, falls into two categories:
Protecting data in transit
Protecting credentials at rest
To protect credentials in transit, I'd recommend using a JDBC driver which supports SSL. Some JDBC drivers support this feature, for example MySQL. Another approach is to tunnel the JDBC traffic over a SSH tunnel.
Protecting credentials at rest (in configuration files) is more difficult and depends on how you plan to invoke liquibase. If you're using ANT, I'd suggest using the answer to this question on how to read encrypted property files.

Logging into oracle db as a global user

We are trying to shape up an old, 2 tier, Delphi based application. It originally uses database authentication, we'd like to transform the db user accounts to global users, so an OID server could perform the authentication instead of the database.
The Delphi program can no longer log into the database if the account is a global user. I'm trying to understand the login protocol, so far without results.
Similar thing happens with SQLDeveloper, I can't connect as a global user. SQLPlus however works with both kinds of users. We checked the information flow with Wireshark. When the dbserver asks back for a password, the SQLPlus sends it, while the SQLDeveloper doesn't send a password when attempting to connect as a global user.
The client sends the application name too in the login request. Is it possible that we have to store the client app name in the LDAP itself?
To connect to Oracle using OID, application must properly configure OCI (Oracle Call Interface). The data access components (which one ?), you are using, must set OCI_ATTR_DISTINGUISHED_NAME session attribute. If that is not done, then you will be not able to connect to Oracle server using ODI and OCI.
You should check your components documentation for this feature. And if it is not implemented, then discuss this issue with the components vendor. Actually, there is not much work to implement, but some work to setup testing environment is required ...

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