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Ubuntu 15.04 USN-2691-1 Critical: Linux Kernel Denial of Service Exploits

Several security issues were fixed in the kernel.. =========================================================================Ubuntu Security Notice USN-2691-1 July 28, 2015 linux vulnerabilities ========================================================================= A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 15.04 Summary: Several security issues were fixed in the kernel. Software Description: - linux: Linux kernel Details: Andy Lutomirski discovered a flaw in the Linux kernel's handling of nested NMIs (non-maskable interrupts). An unprivileged local user could exploit this flaw to cause a denial of service (system crash) or potentially escalate their privileges. (CVE-2015-3290) Colin King discovered a flaw in the add_key function of the Linux kernel's keyring subsystem. A local user could exploit this flaw to cause a denial of service (memory exhaustion). (CVE-2015-1333) Andy Lutomirski discovered a flaw that allows user to cause the Linux kernel to ignore some NMIs (non-maskable interrupts). A local unprivileged user could exploit this flaw to potentially cause the system to miss important NMIs resulting in unspecified effects. (CVE-2015-3291) Andy Lutomirski and Petr Matousek discovered that an NMI (non-maskable interrupt) that interrupts userspace and encounters an IRET fault is incorrectly handled by the Linux kernel. An unprivileged local user could exploit this flaw to cause a denial of service (kernel OOPs), corruption, or potentially escalate privileges on the system. (CVE-2015-5157) Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 15.04: linux-image-3.19.0-25-generic 3.19.0-25.26 linux-image-3.19.0-25-generic-lpae 3.19.0-25.26 linux-image-3.19.0-25-lowlatency 3.19.0-25.26 linux-image-3.19.0-25-powerpc-e500mc 3.19.0-25.26 linux-image-3.19.0-25-powerpc-smp 3.19.0-25.26 linux-image-3.19.0-25-powerpc64-emb 3.19.0-25.26 linux-image-3.19.0-25-powerpc64-smp 3.19.0-25.26 After a standard system update you need to reboot your computer to make all the necessary changes. ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. If you use linux-restricted-modules, you have to update that package as well to get modules which work with the new kernel version. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-server, linux-powerpc), a standard system upgrade will automatically perform this as well. References: https://ubuntu.com/security/notices/USN-2691-1 CVE-2015-1333, CVE-2015-3290, CVE-2015-3291, CVE-2015-5157 Package Information: https://launchpad.net/ubuntu/+source/linux/3.19.0-25.26 . Ubuntu 15.04 addresses kernel vulnerabilities, mitigating risks associated with denial of service and providing comprehensive exploit information for end-users.. Ubuntu Kernel Security, Linux Kernel Update, Security Fixes. . Severity: Critical. LinuxSecurity.com Team

Jul 28, 2015 •Critical Ubuntu