Several security issues were fixed in the Linux kernel.
Mohamed Ghannam discovered that the IPv4 raw socket implementation in the Linux kernel contained a race condition leading to uninitialized pointer usage. A local attacker could use this to cause a denial of service or possibly execute arbitrary code. (CVE-2017-17712)
22 February 2018
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in the Linux kernel.
Mohamed Ghannam discovered that the IPv4 raw socket implementation in the Linux kernel contained a race condition leading to uninitialized pointer usage. A local attacker could use this to cause a denial of service or possibly execute arbitrary code. (CVE-2017-17712)
Laurent Guerby discovered that the mbcache feature in the ext2 and ext4 filesystems in the Linux kernel improperly handled xattr block caching. A local attacker could use this to cause a denial of service. (CVE-2015-8952)
Vitaly Mayatskikh discovered that the SCSI subsystem in the Linux kernel did not properly track reference counts when merging buffers. A local attacker could use this to cause a denial of service (memory exhaustion). (CVE-2017-12190)
ChunYu Wang discovered that a use-after-free vulnerability existed in the SCTP protocol implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code, (CVE-2017-15115)
Mohamed Ghannam discovered a use-after-free vulnerability in the DCCP protocol implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2017-8824)
USN-3540-1 mitigated CVE-2017-5715 (Spectre Variant 2) for the amd64 architecture in Ubuntu 16.04 LTS. This update provides the compiler-based retpoline kernel mitigation for the amd64 and i386 architectures. Original advisory details:
Jann Horn discovered that microprocessors utilizing speculative execution and branch prediction may allow unauthorized memory reads via sidechannel attacks. This flaw is known as Spectre. A local attacker could use this to expose sensitive information, including kernel memory. (CVE-2017-5715)
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
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.
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