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Debian DLA-1466-1 : linux-4.9 security update

high Nessus Plugin ID 111763

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Synopsis

The remote Debian host is missing a security update.

Description

Several vulnerabilities have been discovered in the Linux kernel that may lead to a privilege escalation or denial of service.

CVE-2018-5390 (SegmentSmack)

Juha-Matti Tilli discovered that a remote attacker can trigger the worst case code paths for TCP stream reassembly with low rates of specially crafted packets, leading to remote denial of service.

CVE-2018-5391 (FragmentSmack)

Juha-Matti Tilli discovered a flaw in the way the Linux kernel handled reassembly of fragmented IPv4 and IPv6 packets. A remote attacker can take advantage of this flaw to trigger time and calculation expensive fragment reassembly algorithms by sending specially crafted packets, leading to remote denial of service.

This is mitigated by reducing the default limits on memory usage for incomplete fragmented packets. The same mitigation can be achieved without the need to reboot, by setting the sysctls :

net.ipv4.ipfrag_high_thresh = 262144 net.ipv6.ip6frag_high_thresh = 262144 net.ipv4.ipfrag_low_thresh = 196608 net.ipv6.ip6frag_low_thresh = 196608

The default values may still be increased by local configuration if necessary.

CVE-2018-13405

Jann Horn discovered that the inode_init_owner function in fs/inode.c in the Linux kernel allows local users to create files with an unintended group ownership allowing attackers to escalate privileges by making a plain file executable and SGID.

For Debian 8 'Jessie', these problems have been fixed in version 4.9.110-3+deb9u2~deb8u1. This update includes fixes for several regressions in the latest point release.

The earlier version 4.9.110-3+deb9u1~deb8u1 included all the above fixes except for CVE-2018-5391, which may be mitigated as explained above.

We recommend that you upgrade your linux-4.9 packages.

NOTE: Tenable Network Security has extracted the preceding description block directly from the DLA security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Solution

Upgrade the affected packages.

See Also

https://lists.debian.org/debian-lts-announce/2018/08/msg00014.html

https://packages.debian.org/source/jessie/linux-4.9

Plugin Details

Severity: High

ID: 111763

File Name: debian_DLA-1466.nasl

Version: 1.7

Type: local

Agent: unix

Published: 8/16/2018

Updated: 8/21/2024

Supported Sensors: Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.4

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.6

Vector: CVSS2#AV:L/AC:L/Au:N/C:P/I:P/A:P

CVSS Score Source: CVE-2018-13405

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 7

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:debian:debian_linux:linux-image-4.9.0-0.bpo.7-amd64, p-cpe:/a:debian:debian_linux:linux-image-4.9.0-0.bpo.7-rt-amd64, p-cpe:/a:debian:debian_linux:linux-image-4.9.0-0.bpo.7-rt-686-pae, p-cpe:/a:debian:debian_linux:linux-image-4.9.0-0.bpo.7-armmp-lpae, p-cpe:/a:debian:debian_linux:linux-image-4.9.0-0.bpo.7-armmp, p-cpe:/a:debian:debian_linux:linux-compiler-gcc-4.9-arm, p-cpe:/a:debian:debian_linux:linux-doc-4.9, p-cpe:/a:debian:debian_linux:linux-image-4.9.0-0.bpo.7-rt-amd64-dbg, p-cpe:/a:debian:debian_linux:linux-image-4.9.0-0.bpo.7-marvell, p-cpe:/a:debian:debian_linux:linux-manual-4.9, p-cpe:/a:debian:debian_linux:linux-headers-4.9.0-0.bpo.7-marvell, p-cpe:/a:debian:debian_linux:linux-image-4.9.0-0.bpo.7-686, p-cpe:/a:debian:debian_linux:linux-perf-4.9, p-cpe:/a:debian:debian_linux:linux-headers-4.9.0-0.bpo.7-all-amd64, p-cpe:/a:debian:debian_linux:linux-headers-4.9.0-0.bpo.7-common-rt, p-cpe:/a:debian:debian_linux:linux-headers-4.9.0-0.bpo.7-rt-686-pae, p-cpe:/a:debian:debian_linux:linux-headers-4.9.0-0.bpo.7-amd64, p-cpe:/a:debian:debian_linux:linux-headers-4.9.0-0.bpo.7-common, p-cpe:/a:debian:debian_linux:linux-support-4.9.0-0.bpo.7, p-cpe:/a:debian:debian_linux:linux-headers-4.9.0-0.bpo.7-rt-amd64, p-cpe:/a:debian:debian_linux:linux-headers-4.9.0-0.bpo.7-686-pae, p-cpe:/a:debian:debian_linux:linux-headers-4.9.0-0.bpo.7-armmp-lpae, p-cpe:/a:debian:debian_linux:linux-headers-4.9.0-0.bpo.7-all, p-cpe:/a:debian:debian_linux:linux-kbuild-4.9, p-cpe:/a:debian:debian_linux:linux-image-4.9.0-0.bpo.7-rt-686-pae-dbg, p-cpe:/a:debian:debian_linux:linux-image-4.9.0-0.bpo.7-686-pae, p-cpe:/a:debian:debian_linux:linux-headers-4.9.0-0.bpo.7-all-armhf, p-cpe:/a:debian:debian_linux:linux-headers-4.9.0-0.bpo.7-all-armel, p-cpe:/a:debian:debian_linux:linux-image-4.9.0-0.bpo.7-686-pae-dbg, p-cpe:/a:debian:debian_linux:linux-headers-4.9.0-0.bpo.7-686, p-cpe:/a:debian:debian_linux:linux-headers-4.9.0-0.bpo.7-armmp, p-cpe:/a:debian:debian_linux:linux-source-4.9, cpe:/o:debian:debian_linux:8.0, p-cpe:/a:debian:debian_linux:linux-image-4.9.0-0.bpo.7-amd64-dbg, p-cpe:/a:debian:debian_linux:linux-headers-4.9.0-0.bpo.7-all-i386

Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 8/15/2018

Reference Information

CVE: CVE-2018-13405, CVE-2018-5390, CVE-2018-5391