Debian DLA-849-1 : linux security update
High Nessus Plugin ID 97640
SynopsisThe remote Debian host is missing a security update.
DescriptionSeveral vulnerabilities have been discovered in the Linux kernel that may lead to a privilege escalation, denial of service or have other impacts.
Jim Mattson discovered that the KVM implementation for Intel x86 processors does not properly handle #BP and #OF exceptions in an L2 (nested) virtual machine. A local attacker in an L2 guest VM can take advantage of this flaw to cause a denial of service for the L1 guest VM.
Alexander Popov discovered a race condition flaw in the n_hdlc line discipline that can lead to a double free. A local unprivileged user can take advantage of this flaw for privilege escalation. On systems that do not already have the n_hdlc module loaded, this can be mitigated by disabling it: echo >> /etc/modprobe.d/disable-n_hdlc.conf install n_hdlc false
Gareth Evans reported that privileged users can map memory at address 0 through the shmat() system call. This could make it easier to exploit other kernel security vulnerabilities via a set-UID program.
Alexander Popov reported a race condition in the SCTP implementation that can be used by local users to cause a denial of service (crash).
The initial fix for this was incorrect and introduced further security issues (CVE-2017-6353). This update includes a later fix that avoids those. On systems that do not already have the sctp module loaded, this can be mitigated by disabling it: echo >> /etc/modprobe.d/disable-sctp.conf install sctp false
Dmitry Vyukov reported a bug in the TCP implementation's handling of urgent data in the splice() system call. This can be used by a remote attacker for denial of service (hang) against applications that read from TCP sockets with splice().
Andrey Konovalov reported that the LLC type 2 implementation incorrectly assigns socket buffer ownership. This might be usable by a local user to cause a denial of service (memory corruption or crash) or privilege escalation. On systems that do not already have the llc2 module loaded, this can be mitigated by disabling it: echo >> /etc/modprobe.d/disable-llc2.conf install llc2 false
Dmitry Vyukov reported a race condition in the raw packet (af_packet) fanout feature. Local users with the CAP_NET_RAW capability (in any user namespace) can use this for denial of service and possibly for privilege escalation.
Dmitry Vyukov reported that the general queue implementation in the IrDA subsystem does not properly manage multiple locks, possibly allowing local users to cause a denial of service (deadlock) via crafted operations on IrDA devices.
For Debian 7 'Wheezy', these problems have been fixed in version 3.2.86-1.
For Debian 8 'Jessie', these problems have been fixed in version 3.16.39-1+deb8u2.
We recommend that you upgrade your linux 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.
SolutionUpgrade the affected linux package.