CVE-2016-5696
Published: 6 August 2016
net/ipv4/tcp_input.c in the Linux kernel before 4.7 does not properly determine the rate of challenge ACK segments, which makes it easier for remote attackers to hijack TCP sessions via a blind in-window attack.
From the Ubuntu Security Team
Yue Cao et al discovered a flaw in the TCP implementation's handling of challenge acks in the Linux kernel. A remote attacker could use this to cause a denial of service (reset connection) or inject content into an TCP stream.
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 | fix is going to land in Ubuntu kernels in this SRU cycle, with a likely release date of Aug 27. Earlier access to the kernels with the fix will be available from the -proposed pocket, though they come with the risk of being less tested. |
Mitigation
Set the net.ipv4.tcp_challenge_ack_limit sysctl to some absurdly large number (as described in the lwn article referenced above)
Priority
Status
Package | Release | Status |
---|---|---|
linux-armadaxp Launchpad, Ubuntu, Debian |
xenial |
Does not exist
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
precise |
Released
(3.2.0-1672.98)
|
|
trusty |
Does not exist
|
|
wily |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
This package is not directly supported by the Ubuntu Security Team | ||
linux-goldfish Launchpad, Ubuntu, Debian |
zesty |
Ignored
(end of life)
|
precise |
Does not exist
|
|
trusty |
Does not exist
(trusty was ignored)
|
|
wily |
Ignored
(end of life)
|
|
xenial |
Ignored
(abandoned)
|
|
yakkety |
Ignored
(end of life)
|
|
upstream |
Released
(4.7)
|
|
linux-grouper Launchpad, Ubuntu, Debian |
precise |
Does not exist
|
trusty |
Does not exist
(trusty was ignored)
|
|
wily |
Does not exist
|
|
xenial |
Does not exist
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-hwe-edge Launchpad, Ubuntu, Debian |
precise |
Does not exist
|
xenial |
Not vulnerable
(4.8.0-36.36~16.04.1)
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
trusty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-linaro-omap Launchpad, Ubuntu, Debian |
precise |
Ignored
(end of life)
|
trusty |
Does not exist
|
|
wily |
Does not exist
|
|
xenial |
Does not exist
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-linaro-shared Launchpad, Ubuntu, Debian |
precise |
Ignored
(end of life)
|
trusty |
Does not exist
|
|
wily |
Does not exist
|
|
xenial |
Does not exist
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-linaro-vexpress Launchpad, Ubuntu, Debian |
precise |
Ignored
(end of life)
|
trusty |
Does not exist
|
|
wily |
Does not exist
|
|
xenial |
Does not exist
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-lts-quantal Launchpad, Ubuntu, Debian |
precise |
Ignored
(end of life)
|
trusty |
Does not exist
|
|
wily |
Does not exist
|
|
xenial |
Does not exist
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
This package is not directly supported by the Ubuntu Security Team | ||
linux-lts-raring Launchpad, Ubuntu, Debian |
precise |
Ignored
(end of life)
|
trusty |
Does not exist
|
|
wily |
Does not exist
|
|
xenial |
Does not exist
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-lts-saucy Launchpad, Ubuntu, Debian |
precise |
Ignored
(end of life)
|
trusty |
Does not exist
|
|
wily |
Does not exist
|
|
xenial |
Does not exist
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
This package is not directly supported by the Ubuntu Security Team | ||
linux-lts-trusty Launchpad, Ubuntu, Debian |
precise |
Released
(3.13.0-95.142~precise1)
|
trusty |
Does not exist
|
|
wily |
Does not exist
|
|
xenial |
Does not exist
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-lts-utopic Launchpad, Ubuntu, Debian |
precise |
Does not exist
|
trusty |
Does not exist
(trusty was ignored [end of standard support])
|
|
wily |
Does not exist
|
|
xenial |
Does not exist
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-lts-vivid Launchpad, Ubuntu, Debian |
precise |
Does not exist
|
trusty |
Released
(3.19.0-68.76~14.04.1)
|
|
wily |
Does not exist
|
|
xenial |
Does not exist
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-lts-wily Launchpad, Ubuntu, Debian |
precise |
Does not exist
|
trusty |
Does not exist
(trusty was ignored [end of standard support])
|
|
wily |
Does not exist
|
|
xenial |
Does not exist
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-lts-xenial Launchpad, Ubuntu, Debian |
precise |
Does not exist
|
trusty |
Released
(4.4.0-36.55~14.04.1)
|
|
wily |
Does not exist
|
|
xenial |
Does not exist
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-maguro Launchpad, Ubuntu, Debian |
precise |
Does not exist
|
trusty |
Does not exist
(trusty was ignored)
|
|
wily |
Does not exist
|
|
xenial |
Does not exist
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-mako Launchpad, Ubuntu, Debian |
precise |
Does not exist
|
trusty |
Does not exist
(trusty was ignored)
|
|
wily |
Not vulnerable
|
|
xenial |
Not vulnerable
|
|
yakkety |
Not vulnerable
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-manta Launchpad, Ubuntu, Debian |
precise |
Does not exist
|
trusty |
Does not exist
(trusty was ignored)
|
|
wily |
Ignored
(end of life)
|
|
xenial |
Does not exist
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-qcm-msm Launchpad, Ubuntu, Debian |
precise |
Ignored
(end of life)
|
trusty |
Does not exist
|
|
wily |
Does not exist
|
|
xenial |
Does not exist
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-raspi2 Launchpad, Ubuntu, Debian |
precise |
Does not exist
|
trusty |
Does not exist
|
|
wily |
Ignored
(end of life)
|
|
xenial |
Released
(4.4.0-1021.27)
|
|
yakkety |
Not vulnerable
(4.8.0-1012.14)
|
|
zesty |
Not vulnerable
(4.8.0-1013.15)
|
|
upstream |
Released
(4.7)
|
|
linux-snapdragon Launchpad, Ubuntu, Debian |
precise |
Does not exist
|
trusty |
Does not exist
|
|
wily |
Does not exist
|
|
xenial |
Released
(4.4.0-1024.27)
|
|
yakkety |
Not vulnerable
(4.4.0-1029.32)
|
|
zesty |
Not vulnerable
(4.4.0-1029.32)
|
|
upstream |
Released
(4.7)
|
|
linux-ti-omap4 Launchpad, Ubuntu, Debian |
precise |
Released
(3.2.0-1487.114)
|
trusty |
Does not exist
|
|
wily |
Does not exist
|
|
xenial |
Does not exist
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux Launchpad, Ubuntu, Debian |
precise |
Released
(3.2.0-109.150)
|
trusty |
Released
(3.13.0-95.142)
|
|
wily |
Ignored
(end of life)
|
|
xenial |
Released
(4.4.0-36.55)
|
|
yakkety |
Not vulnerable
(4.8.0-11.12)
|
|
zesty |
Not vulnerable
(4.8.0-22.24)
|
|
upstream |
Released
(4.7)
|
|
Patches: Introduced by 282f23c6ee343126156dd41218b22ece96d747e3 |
||
linux-flo Launchpad, Ubuntu, Debian |
precise |
Does not exist
|
trusty |
Does not exist
(trusty was ignored)
|
|
wily |
Not vulnerable
|
|
xenial |
Not vulnerable
|
|
yakkety |
Not vulnerable
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-aws Launchpad, Ubuntu, Debian |
precise |
Does not exist
|
trusty |
Not vulnerable
(4.4.0-1002.2)
|
|
xenial |
Not vulnerable
(4.4.0-1001.10)
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-hwe Launchpad, Ubuntu, Debian |
precise |
Does not exist
|
trusty |
Does not exist
|
|
xenial |
Not vulnerable
(4.8.0-36.36~16.04.1)
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
|
linux-gke Launchpad, Ubuntu, Debian |
precise |
Does not exist
|
trusty |
Does not exist
|
|
xenial |
Not vulnerable
(4.4.0-1003.3)
|
|
yakkety |
Does not exist
|
|
zesty |
Does not exist
|
|
upstream |
Released
(4.7)
|
Severity score breakdown
Parameter | Value |
---|---|
Base score | 4.8 |
Attack vector | Network |
Attack complexity | High |
Privileges required | None |
User interaction | None |
Scope | Unchanged |
Confidentiality | None |
Integrity impact | Low |
Availability impact | Low |
Vector | CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L |
References
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-5696
- https://www.mail-archive.com/netdev@vger.kernel.org/msg118677.html
- http://git.kernel.org/cgit/linux/kernel/git/davem/net.git/commit/?id=75ff39ccc1bd5d3c455b6822ab09e533c551f758
- https://lwn.net/Articles/696868/
- https://ubuntu.com/security/notices/USN-3072-1
- https://ubuntu.com/security/notices/USN-3072-2
- https://ubuntu.com/security/notices/USN-3070-1
- https://ubuntu.com/security/notices/USN-3071-2
- https://ubuntu.com/security/notices/USN-3071-1
- https://ubuntu.com/security/notices/USN-3070-4
- https://ubuntu.com/security/notices/USN-3070-3
- https://ubuntu.com/security/notices/USN-3070-2
- NVD
- Launchpad
- Debian