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redhatRedHatRHSA-2018:2785
HistorySep 25, 2018 - 7:35 p.m.

(RHSA-2018:2785) Important: kernel security and bug fix update

2018-09-2519:35:35
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115

CVSS2

7.8

Attack Vector

NETWORK

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

COMPLETE

AV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS3

7.8

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

0.783

Percentile

98.3%

The kernel packages contain the Linux kernel, the core of any Linux operating system.

Security Fix(es):

  • A flaw named SegmentSmack was found in the way the Linux kernel handled specially crafted TCP packets. A remote attacker could use this flaw to trigger time and calculation expensive calls to tcp_collapse_ofo_queue() and tcp_prune_ofo_queue() functions by sending specially modified packets within ongoing TCP sessions which could lead to a CPU saturation and hence a denial of service on the system. Maintaining the denial of service condition requires continuous two-way TCP sessions to a reachable open port, thus the attacks cannot be performed using spoofed IP addresses. (CVE-2018-5390)

  • A flaw named FragmentSmack was found in the way the Linux kernel handled reassembly of fragmented IPv4 and IPv6 packets. A remote attacker could use this flaw to trigger time and calculation expensive fragment reassembly algorithm by sending specially crafted packets which could lead to a CPU saturation and hence a denial of service on the system. (CVE-2018-5391)

  • kernel: mm: use-after-free in do_get_mempolicy function allows local DoS or other unspecified impact (CVE-2018-10675)

For more details about the security issue(s), including the impact, a CVSS score, and other related information, refer to the CVE page(s) listed in the References section.

Red Hat would like to thank Juha-Matti Tilli (Aalto University - Department of Communications and Networking and Nokia Bell Labs) for reporting CVE-2018-5390 and CVE-2018-5391.

Bug Fix(es):

  • On systems running Red Hat Enterprise Linux 7 with Red Hat OpenShift Container Platform 3.5, a node sometimes got into “NodeNotReady” state after a CPU softlockup. Consequently, the node was not available. This update fixes an irq latency source in memory compaction. As a result, nodes no longer get into “NodeNotReady” state under the described circumstances. (BZ#1596281)

  • Previously, the kernel source code was missing support to report the Speculative Store Bypass Disable (SSBD) vulnerability status on IBM Power Systems and the little-endian variants of IBM Power Systems. As a consequence, the /sys/devices/system/cpu/vulnerabilities/spec_store_bypass file incorrectly reported “Not affected” on both CPU architectures. This fix updates the kernel source code to properly report the SSBD status either as “Vulnerable” or “Mitigation: Kernel entry/exit barrier (TYPE)” where TYPE is one of “eieio”, “hwsync”, “fallback”, or “unknown”. (BZ#1612351)

  • The hypervisors of Red Hat Enterprise Linux 7 virtual machines (VMs) in certain circumstances mishandled the microcode update in the kernel. As a consequence, the VMs sometimes became unresponsive when booting. This update applies an upstream patch to avoid early microcode update when running under a hypervisor. As a result, kernel hangs no longer occur in the described scenario. (BZ#1618388)

CVSS2

7.8

Attack Vector

NETWORK

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

COMPLETE

AV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS3

7.8

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

0.783

Percentile

98.3%