Security Bulletin: Vulnerabilities in the Linux kernel affect PowerKVM

Summary

PowerKVM is affected by vulnerabilities in the Linux kernel. IBM has now addressed these vulnerabilities.

Vulnerability Details

CVEID: CVE-2016-5195**
DESCRIPTION:** Linux Kernel could allow a local attacker to gain elevated privileges on the system, caused by a race condition when handling the copy-on-write (COW) breakage of private read-only memory mappings by the memory subsystem. An attacker could exploit this vulnerability to gain write access to read-only memory mappings and elevated privileges on the system. Note: This vulnerability is known as the Dirty COW bug.
CVSS Base Score: 8.4
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/118170 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)

CVEID: CVE-2016-3134**
DESCRIPTION:** Linux Kernel could allow a remote attacker to execute arbitrary code on the system, caused by an out-of-bounds write in the IPT_SO_SET_REPLACE ioctl within netfilter code for iptables support. An attacker could exploit this vulnerability to corrupt heap memory and execute arbitrary code on the system.
CVSS Base Score: 7.3
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/111418 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L)

CVEID: CVE-2016-4997**
DESCRIPTION:** Linux Kernel could allow a local attacker to gain elevated privileges on the system, caused by a memory corruption error in the IPT_SO_SET_REPLACE compat_setsockopt() function. A local attacker could exploit this vulnerability to gain kernel-like privileges on the system.
CVSS Base Score: 8.4
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/114454 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)

CVEID: CVE-2016-4998**
DESCRIPTION:** Linux Kernel is vulnerable to a denial of service, caused by a out-of-bounds memory access error. By sending a specially crafted IPT_SO_SET_REPLACE setsockopt() call, an attacker could exploit this vulnerability to cause the system to crash.
CVSS Base Score: 6.2
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/114455 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

CVEID: CVE-2016-5696**
DESCRIPTION:** Linux Kernel could allow a remote attacker to obtain sensitive information, caused by the failure to properly determine the rate of challenge ACK segments by net/ipv4/tcp_input.c. An attacker could exploit this vulnerability using a blind in-window attack to inject or control the contents of a TCP stream in a connection between a Linux device and its connected client or server, making it easier to hijack TCP sessions.
CVSS Base Score: 5.9
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/116101 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N)

Affected Products and Versions

PowerKVM 2.1 and PowerKVM 3.1.

Remediation/Fixes

Customers can update PowerKVM systems by using “yum update”.

Fix images are made available via Fix Central. For version 3.1, see https://ibm.biz/BdHggw. This issue is addressed as of 3.1.0.2 update 3 or later.

For version 2.1, see https://ibm.biz/BdEnT8. This issue is addressed as of PowerKVM 2.1.1.3-65 update 13 or later. Customers running v2.1 are, in any case, encouraged to upgrade to v3.1.

For v2.1 systems currently running fix levels of PowerKVM prior to 2.1.1, please see <http://download4.boulder.ibm.com/sar/CMA/OSA/05e4c/0/README&gt; for prerequisite fixes and instructions.