Red Hat Identity Management is a centralized authentication, identity management and authorization solution for both traditional and cloud-based enterprise environments.
A weakness was found in the way IPA clients communicated with IPA servers when initially attempting to join IPA domains. As there was no secure way to provide the IPA server's Certificate Authority (CA) certificate to the client during a join, the IPA client enrollment process was susceptible to man-in-the-middle attacks. This flaw could allow an attacker to obtain access to the IPA server using the credentials provided by an IPA client, including administrative access to the entire domain if the join was performed using an administrator's credentials. (CVE-2012-5484)
Note: This weakness was only exposed during the initial client join to the realm, because the IPA client did not yet have the CA certificate of the server. Once an IPA client has joined the realm and has obtained the CA certificate of the IPA server, all further communication is secure. If a client were using the OTP (one-time password) method to join to the realm, an attacker could only obtain unprivileged access to the server (enough to only join the realm).
Red Hat would like to thank Petr Mensik for reporting this issue.
When a fix for this flaw has been applied to the client but not yet the server, ipa-client-install, in unattended mode, will fail if you do not have the correct CA certificate locally, noting that you must use the "--force" option to insecurely obtain the certificate. In interactive mode, the certificate will try to be obtained securely from LDAP. If this fails, you will be prompted to insecurely download the certificate via HTTP. In the same situation when using OTP, LDAP will not be queried and you will be prompted to insecurely download the certificate via HTTP.
Users of ipa-client are advised to upgrade to this updated package, which corrects this issue.