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Ubuntu 24.04 LTS USN-7542-1 Critical: Kerberos Network Exposure

Kerberos could be made to expose sensitive information over the network.. ========================================================================== Ubuntu Security Notice USN-7542-1 May 28, 2025 krb5 vulnerability ========================================================================== A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 24.04 LTS - Ubuntu 22.04 LTS - Ubuntu 20.04 LTS - Ubuntu 18.04 LTS - Ubuntu 16.04 LTS - Ubuntu 14.04 LTS Summary: Kerberos could be made to expose sensitive information over the network. Software Description: - krb5: MIT Kerberos Network Authentication Protocol Details: It was discovered that Kerberos allowed the usage of weak cryptographic standards. An attacker could possibly use this issue to expose sensitive information. This update introduces the allow_rc4 and allow_des3 configuration options, and disables the usage of RC4 and 3DES ciphers by default. Users are advised to discontinue their usage and upgrade to stronger encryption protocols. If the use of the insecure RC4 and 3DES algorithms is necessary, they can be enabled with the aforementioned configuration options. Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 24.04 LTS libk5crypto3 1.20.1-6ubuntu2.6 libkrb5-3 1.20.1-6ubuntu2.6 Ubuntu 22.04 LTS libk5crypto3 1.19.2-2ubuntu0.7 libkrb5-3 1.19.2-2ubuntu0.7 Ubuntu 20.04 LTS libk5crypto3 1.17-6ubuntu4.11 libkrb5-3 1.17-6ubuntu4.11 Ubuntu 18.04 LTS libk5crypto3 1.16-2ubuntu0.4+esm5 Available with Ubuntu Pro libkrb5-3 1.16-2ubuntu0.4+esm5 Available with Ubuntu Pro Ubuntu 16.04 LTS libk5crypto3 1.13.2+dfsg-5ubuntu2.2+esm7 Available with Ubuntu Pro libkrb5-3 1.13.2+dfsg-5ubuntu2.2+esm7 Available with Ubuntu Pro Ubuntu 14.04 LTS libk5crypto3 1.12+dfsg-2ubuntu5.4+esm7 Available with Ubuntu Pro libkrb5-3 1.12+dfsg-2ubuntu5.4+esm7 Available with Ubuntu Pro In general, a standard system update will make all the necessary changes. References: https://ubuntu.com/security/notices/USN-7542-1 CVE-2025-3576 Package Information: https://launchpad.net/ubuntu/+source/krb5/1.20.1-6ubuntu2.6 https://launchpad.net/ubuntu/+source/krb5/1.19.2-2ubuntu0.7 https://launchpad.net/ubuntu/+source/krb5/1.17-6ubuntu4.11 . A newly discovered weakness in Kerberos can leak critical data via network traffic. To bolster your system's security, promptly update your Ubuntu machine.. Kerberos, network security, Ubuntu updates, cryptography. . Severity: Critical. LinuxSecurity.com Team

May 28, 2025 •Critical Ubuntu