============================================================================ Ubuntu Security Notice USN-2854-1 December 20, 2015 linux-lts-vivid vulnerabilities ============================================================================ A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 14.04 LTS Summary: Several security issues were fixed in the kernel. Software Description: - linux-lts-vivid: Linux hardware enablement kernel from Vivid Details: Felix Wilhelm discovered a race condition in the Xen paravirtualized drivers which can cause double fetch vulnerabilities. An attacker in the paravirtualized guest could exploit this flaw to cause a denial of service (crash the host) or potentially execute arbitrary code on the host. (CVE-2015-8550) Konrad Rzeszutek Wilk discovered the Xen PCI backend driver does not perform sanity checks on the device's state. An attacker could exploit this flaw to cause a denial of service (NULL dereference) on the host. (CVE-2015-8551) Konrad Rzeszutek Wilk discovered the Xen PCI backend driver does not perform sanity checks on the device's state. An attacker could exploit this flaw to cause a denial of service by flooding the logging system with WARN() messages causing the initial domain to exhaust disk space. (CVE-2015-8552) Jann Horn discovered a ptrace issue with user namespaces in the Linux kernel. The namespace owner could potentially exploit this flaw by ptracing a root owned process entering the user namespace to elevate its privileges and potentially gain access outside of the namespace. (http://bugs.launchpad.net/bugs/1527374) Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 14.04 LTS: linux-image-3.19.0-42-generic 3.19.0-42.48~14.04.1 linux-image-3.19.0-42-generic-lpae 3.19.0-42.48~14.04.1 linux-image-3.19.0-42-lowlatency 3.19.0-42.48~14.04.1 linux-image-3.19.0-42-powerpc-e500mc 3.19.0-42.48~14.04.1 linux-image-3.19.0-42-powerpc-smp 3.19.0-42.48~14.04.1 linux-image-3.19.0-42-powerpc64-emb 3.19.0-42.48~14.04.1 linux-image-3.19.0-42-powerpc64-smp 3.19.0-42.48~14.04.1 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. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual, linux-powerpc), a standard system upgrade will automatically perform this as well. References: http://www.ubuntu.com/usn/usn-2854-1 CVE-2015-8550, CVE-2015-8551, CVE-2015-8552, http://bugs.launchpad.net/bugs/1527374 Package Information: https://launchpad.net/ubuntu/+source/linux-lts-vivid/3.19.0-42.48~14.04.1