CVE-2016-4997

Published: 24 June 2016

The compat IPT_SO_SET_REPLACE and IP6T_SO_SET_REPLACE setsockopt implementations in the netfilter subsystem in the Linux kernel before 4.6.3 allow local users to gain privileges or cause a denial of service (memory corruption) by leveraging in-container root access to provide a crafted offset value that triggers an unintended decrement.

From the Ubuntu Security Team

Jesse Hertz and Tim Newsham discovered that the Linux netfilter implementation did not correctly perform validation when handling 32 bit compatibility IPT_SO_SET_REPLACE events on 64 bit platforms. A local unprivileged attacker could use this to cause a denial of service (system crash) or execute arbitrary code with administrative privileges.

Notes

Author	Note
jdstrand	android kernels (flo, goldfish, grouper, maguro, mako and manta) are not supported on the Ubuntu Touch 14.10 and earlier preview kernels linux-lts-saucy no longer receives official support linux-lts-quantal no longer receives official support
sbeattie	priority is negligible on precise's 3.2 kernels, as user namespaces are a privileged operation there. For xenial and linux-lts-xenial on trusty, this can be mitigated against by setting the kernel.unprivileged_userns_clone sysctl to 0 to disable userns support. When we fix the netfilter issue we will also add this sysctl to all other supported kernels to allow disabling unprivileged user namespaces. Disabling user namespace may impact chromium-browser, lxc, lxd, docker, and other tools.

Author

Note

jdstrand

android kernels (flo, goldfish, grouper, maguro, mako and manta) are
not supported on the Ubuntu Touch 14.10 and earlier preview kernels
linux-lts-saucy no longer receives official support
linux-lts-quantal no longer receives official support

sbeattie

priority is negligible on precise's 3.2 kernels, as user
namespaces are a privileged operation there.
For xenial and linux-lts-xenial on trusty, this can be
mitigated against by setting the kernel.unprivileged_userns_clone
sysctl to 0 to disable userns support. When we fix the netfilter issue
we will also add this sysctl to all other supported kernels to allow
disabling unprivileged user namespaces. Disabling user namespace may
impact chromium-browser, lxc, lxd, docker, and other tools.

Priority

Cvss 3 Severity Score

7.8

Score breakdown

Status

Package	Release	Status
linux Launchpad, Ubuntu, Debian	artful	Not vulnerable (4.10.0-19.21)
	precise	Released (3.2.0-128.173)
	trusty	Released (3.13.0-91.138)
	upstream	Released (4.7~rc1)
	wily	Released (4.2.0-41.48)
	xenial	Released (4.4.0-28.47)
	yakkety	Not vulnerable (4.4.0-28.47)
	zesty	Not vulnerable (4.8.0-22.24)
	Patches: Introduced by 2722971cbe831117686039d5c334f2c0f560be13 Fixed by ce683e5f9d045e5d67d1312a42b359cb2ab2a13c Introduced by 2722971cbe831117686039d5c334f2c0f560be13 Fixed by 6e94e0cfb0887e4013b3b930fa6ab1fe6bb6ba91 Introduced by 2722971cbe831117686039d5c334f2c0f560be13 Fixed by bdf533de6968e9686df777dc178486f600c6e617
linux-armadaxp Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist (precise was needed)
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	wily	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
	This package is not directly supported by the Ubuntu Security Team
linux-aws Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Not vulnerable (4.4.0-1002.2)
	upstream	Released (4.7~rc1)
	xenial	Not vulnerable (4.4.0-1001.10)
	yakkety	Does not exist
	zesty	Does not exist
linux-azure Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Not vulnerable (4.15.0-1023.24~14.04.1)
	upstream	Released (4.7~rc1)
	xenial	Not vulnerable (4.11.0-1009.9)
	yakkety	Does not exist
	zesty	Does not exist
linux-euclid Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	xenial	Not vulnerable (4.4.0-9019.20)
	zesty	Does not exist
linux-flo Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	upstream	Released (4.7~rc1)
	wily	Ignored (reached end-of-life)
	xenial	Ignored (abandoned)
	yakkety	Ignored (abandoned)
	zesty	Does not exist
linux-gcp Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	xenial	Not vulnerable (4.10.0-1004.4)
	yakkety	Does not exist
	zesty	Does not exist
linux-gke Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	xenial	Not vulnerable (4.4.0-1003.3)
	yakkety	Does not exist
	zesty	Does not exist
linux-goldfish Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	upstream	Released (4.7~rc1)
	wily	Ignored (reached end-of-life)
	xenial	Ignored (abandoned)
	yakkety	Ignored (abandoned)
	zesty	Ignored (abandoned)
linux-grouper Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	upstream	Released (4.7~rc1)
	wily	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-hwe Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	xenial	Not vulnerable (4.8.0-36.36~16.04.1)
	yakkety	Does not exist
	zesty	Does not exist
linux-hwe-edge Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	xenial	Not vulnerable (4.8.0-36.36~16.04.1)
	yakkety	Does not exist
	zesty	Does not exist
linux-kvm Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	xenial	Not vulnerable (4.4.0-1004.9)
	zesty	Does not exist
linux-linaro-omap Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist (precise was ignored [abandoned])
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	wily	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-linaro-shared Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist (precise was ignored [abandoned])
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	wily	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-linaro-vexpress Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist (precise was ignored [abandoned])
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	wily	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-quantal Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist (precise was ignored [end-of-life])
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	wily	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
	This package is not directly supported by the Ubuntu Security Team
linux-lts-raring Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist (precise was ignored [end-of-life])
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	wily	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-saucy Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist (precise was ignored [end-of-life])
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	wily	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
	This package is not directly supported by the Ubuntu Security Team
linux-lts-trusty Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Released (3.13.0-91.138~precise1)
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	wily	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-utopic Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist (trusty was released [3.16.0-76.98~14.04.1])
	upstream	Released (4.7~rc1)
	wily	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-vivid Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist (trusty was released [3.19.0-64.72~14.04.1])
	upstream	Released (4.7~rc1)
	wily	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-wily Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist (trusty was released [4.2.0-41.48~14.04.1])
	upstream	Released (4.7~rc1)
	wily	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-xenial Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Released (4.4.0-28.47~14.04.1)
	upstream	Released (4.7~rc1)
	wily	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-maguro Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	upstream	Released (4.7~rc1)
	wily	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-mako Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	upstream	Released (4.7~rc1)
	wily	Ignored (reached end-of-life)
	xenial	Ignored (abandoned)
	yakkety	Ignored (abandoned)
	zesty	Does not exist
linux-manta Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	upstream	Released (4.7~rc1)
	wily	Ignored (reached end-of-life)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-oem Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	xenial	Not vulnerable (4.13.0-1008.9)
	zesty	Does not exist
linux-qcm-msm Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist (precise was ignored [abandoned])
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	wily	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-raspi2 Launchpad, Ubuntu, Debian	artful	Not vulnerable (4.10.0-1004.6)
	precise	Does not exist
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	wily	Released (4.2.0-1033.43)
	xenial	Released (4.4.0-1016.22)
	yakkety	Not vulnerable (4.4.0-1016.22)
	zesty	Not vulnerable (4.8.0-1013.15)
linux-snapdragon Launchpad, Ubuntu, Debian	artful	Not vulnerable (4.4.0-1050.54)
	precise	Does not exist
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	wily	Does not exist
	xenial	Released (4.4.0-1019.22)
	yakkety	Not vulnerable (4.4.0-1019.22)
	zesty	Not vulnerable (4.4.0-1029.32)
linux-ti-omap4 Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Does not exist (precise was needed)
	trusty	Does not exist
	upstream	Released (4.7~rc1)
	wily	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist

Severity score breakdown

Parameter	Value
Base score	7.8
Attack vector	Local
Attack complexity	Low
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality	High
Integrity impact	High
Availability impact	High
Vector	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

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