ALAS-2019-1293

Related Vulnerabilities: CVE-2019-14821   CVE-2019-14835  

An out-of-bounds access issue was found in the way Linux kernel's KVM hypervisor implements the Coalesced MMIO write operation. It operates on an MMIO ring buffer 'struct kvm_coalesced_mmio' object, wherein write indices 'ring->first' and 'ring->last' value could be supplied by a host user-space process. An unprivileged host user or process with access to '/dev/kvm' device could use this flaw to crash the host kernel, resulting in a denial of service or potentially escalating privileges on the system. (CVE-2019-14821) A buffer overflow flaw was found in the way Linux kernel's vhost functionality that translates virtqueue buffers to IOVs, logged the buffer descriptors during migration. A privileged guest user able to pass descriptors with invalid length to the host when migration is underway, could use this flaw to increase their privileges on the host.(CVE-2019-14835)

ALAS-2019-1293


Amazon Linux AMI Security Advisory: ALAS-2019-1293
Advisory Release Date: 2019-09-25 23:01 Pacific
Advisory Updated Date: 2019-10-09 23:08 Pacific
Severity: Important

Issue Overview:

An out-of-bounds access issue was found in the way Linux kernel's KVM hypervisor implements the Coalesced MMIO write operation. It operates on an MMIO ring buffer 'struct kvm_coalesced_mmio' object, wherein write indices 'ring->first' and 'ring->last' value could be supplied by a host user-space process. An unprivileged host user or process with access to '/dev/kvm' device could use this flaw to crash the host kernel, resulting in a denial of service or potentially escalating privileges on the system. (CVE-2019-14821)

A buffer overflow flaw was found in the way Linux kernel's vhost functionality that translates virtqueue buffers to IOVs, logged the buffer descriptors during migration. A privileged guest user able to pass descriptors with invalid length to the host when migration is underway, could use this flaw to increase their privileges on the host.(CVE-2019-14835)


Affected Packages:

kernel


Issue Correction:
Run yum update kernel to update your system.

New Packages:
i686:
    kernel-debuginfo-4.14.146-93.123.amzn1.i686
    kernel-4.14.146-93.123.amzn1.i686
    kernel-tools-devel-4.14.146-93.123.amzn1.i686
    kernel-headers-4.14.146-93.123.amzn1.i686
    kernel-debuginfo-common-i686-4.14.146-93.123.amzn1.i686
    perf-debuginfo-4.14.146-93.123.amzn1.i686
    kernel-devel-4.14.146-93.123.amzn1.i686
    perf-4.14.146-93.123.amzn1.i686
    kernel-tools-4.14.146-93.123.amzn1.i686
    kernel-tools-debuginfo-4.14.146-93.123.amzn1.i686

src:
    kernel-4.14.146-93.123.amzn1.src

x86_64:
    kernel-debuginfo-common-x86_64-4.14.146-93.123.amzn1.x86_64
    perf-4.14.146-93.123.amzn1.x86_64
    kernel-headers-4.14.146-93.123.amzn1.x86_64
    kernel-tools-4.14.146-93.123.amzn1.x86_64
    kernel-tools-devel-4.14.146-93.123.amzn1.x86_64
    kernel-tools-debuginfo-4.14.146-93.123.amzn1.x86_64
    kernel-devel-4.14.146-93.123.amzn1.x86_64
    kernel-4.14.146-93.123.amzn1.x86_64
    kernel-debuginfo-4.14.146-93.123.amzn1.x86_64
    perf-debuginfo-4.14.146-93.123.amzn1.x86_64