[SECURITY] [DSA 3659-1] linux security update

ID DEBIAN:DSA-3659-1:3F508
Type debian
Reporter Debian
Modified 2016-09-04T17:25:13


Debian Security Advisory DSA-3659-1 security@debian.org https://www.debian.org/security/ Salvatore Bonaccorso September 04, 2016 https://www.debian.org/security/faq

Package : linux CVE ID : CVE-2016-5696 CVE-2016-6136 CVE-2016-6480 CVE-2016-6828

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


Yue Cao, Zhiyun Qian, Zhongjie Wang, Tuan Dao, and Srikanth V.
Krishnamurthy of the University of California, Riverside; and Lisa
M. Marvel of the United States Army Research Laboratory discovered
that Linux's implementation of the TCP Challenge ACK feature
results in a side channel that can be used to find TCP connections
between specific IP addresses, and to inject messages into those

Where a service is made available through TCP, this may allow
remote attackers to impersonate another connected user to the
server or to impersonate the server to another connected user.  In
case the service uses a protocol with message authentication
(e.g. TLS or SSH), this vulnerability only allows denial of
service (connection failure).  An attack takes tens of seconds, so
short-lived TCP connections are also unlikely to be vulnerable.

This may be mitigated by increasing the rate limit for TCP
Challenge ACKs so that it is never exceeded:
    sysctl net.ipv4.tcp_challenge_ack_limit=1000000000


Pengfei Wang discovered that the audit subsystem has a
'double-fetch' or 'TOCTTOU' bug in its handling of special
characters in the name of an executable.  Where audit logging of
execve() is enabled, this allows a local user to generate
misleading log messages.


Pengfei Wang discovered that the aacraid driver for Adaptec RAID
controllers has a 'double-fetch' or 'TOCTTOU' bug in its
validation of 'FIB' messages passed through the ioctl() system
call.  This has no practical security impact in current Debian


Marco Grassi reported a 'use-after-free' bug in the TCP
implementation, which can be triggered by local users.  The
security impact is unclear, but might include denial of service or
privilege escalation.

For the stable distribution (jessie), these problems have been fixed in version 3.16.36-1+deb8u1. In addition, this update contains several changes originally targeted for the upcoming jessie point release.

We recommend that you upgrade your linux packages.

Further information about Debian Security Advisories, how to apply these updates to your system and frequently asked questions can be found at: https://www.debian.org/security/

Mailing list: debian-security-announce@lists.debian.org