Debian DSA-4078-1 : linux - security update (Meltdown)
Medium Nessus Plugin ID 105595
SynopsisThe remote Debian host is missing a security-related update.
DescriptionMultiple researchers have discovered a vulnerability in Intel processors, enabling an attacker controlling an unprivileged process to read memory from arbitrary addresses, including from the kernel and all other processes running on the system.
This specific attack has been named Meltdown and is addressed in the Linux kernel for the Intel x86-64 architecture by a patch set named Kernel Page Table Isolation, enforcing a near complete separation of the kernel and userspace address maps and preventing the attack. This solution might have a performance impact, and can be disabled at boot time by passing pti=off to the kernel command line.
We also identified a regression for ancient userspaces using the vsyscall interface, for example chroot and containers using (e)glibc 2.13 and older, including those based on Debian 7 or RHEL/CentOS 6.
This regression will be fixed in a later update.
The other vulnerabilities (named Spectre) published at the same time are not addressed in this update and will be fixed in a later update.
SolutionUpgrade the linux packages.
For the oldstable distribution (jessie), this problem will be fixed in a separate update.
For the stable distribution (stretch), this problem has been fixed in version 4.9.65-3+deb9u2.