An updated ipa-client package that fixes one security issue is nowavailable for Red Hat Enterprise Linux 5. The Red Hat Security Response Team has rated this update as having important security impact. A Common Vulnerability Scoring System base score, which gives a detailed severity rating, is available from theCVE link in the References section. Red Hat Identity Management is a centralized authentication, identitymanagement and authorization solution for both traditional and cloud-basedenterprise environments.A weakness was found in the way IPA clients communicated with IPA server swhen initially attempting to join IPA domains. As there was no secure way to provide the IPA server's Certificate Authority 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 obtainaccess 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. 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 CAcertificate of the IPA server, all further communication is secure. If a client were using the OTP method to join to the realm,an attacker could only obtain unprivileged access to the server. Red Hat would like to thank Petr Menšík 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 nothave 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. Inthe same situation when using OTP, LDAP will not be queried and you will beprompted to insecurely download the certificate via HTTP. Users of ipa-client are advised to upgrade to this updated package, which corrects this issue.