SECURITY

USN-3833-1: Linux kernel (AWS) vulnerabilities linux-aws vulnerabilities A security issue affects these releases of Ubuntu and its derivatives: Ubuntu 18.04 LTS Summary Several security issues were fixed in the Linux kernel. Software Description linux-aws – Linux kernel for Amazon Web Services (AWS) systems Details Jann Horn discovered that the Linux kernel mishandles mapping UID or GID ranges inside nested user namespaces in some situations. A local attacker could use this to bypass access controls on resources outside the namespace. (CVE-2018-18955) Philipp Wendler discovered that the overlayfs implementation in the Linux kernel did not properly verify the directory contents permissions from within a unprivileged user namespace. A local attacker could use this to expose sensitive information (protected file names). (CVE-2018-6559) Update instructions The problem can be corrected by updating your system to the following package versions: Ubuntu 18.04 LTS linux-image-4.15.0-1029-aws – [ more… ]

USN-3832-1: Linux kernel (AWS) vulnerabilities linux-aws vulnerabilities A security issue affects these releases of Ubuntu and its derivatives: Ubuntu 18.10 Summary Several security issues were fixed in the Linux kernel. Software Description linux-aws – Linux kernel for Amazon Web Services (AWS) systems Details Jann Horn discovered that the procfs file system implementation in the Linux kernel did not properly restrict the ability to inspect the kernel stack of an arbitrary task. A local attacker could use this to expose sensitive information. (CVE-2018-17972) Jann Horn discovered that the mremap() system call in the Linux kernel did not properly flush the TLB when completing, potentially leaving access to a physical page after it has been released to the page allocator. A local attacker could use this to cause a denial of service (system crash), expose sensitive information, or possibly execute arbitrary code. [ more… ]