February 22, 2016

GLIBC Bug in Linux

On Tuesday 16th February 2016, Google and Red Hat engineers announced they had identified a Linux vulnerability with the GNU C Library (glibc) that could be used to perform remote code execution.  This could be exploited by overloading and thus crash server services, or even be used to run malicious code.

The Google, Red Hat and glibc teams swiftly worked together to produce and release a patch to their library.  This was in turn adopted by the various Linux operating system vendors, who have now released their own OS specific versions.

Elive have updated their servers to the new glibc version already and are restarting servers during out of office hours (1 – 4 am) so as to minimise disruption.

For clients with dedicated or virtual servers running linux, we recommend you update your server immediately using the following instructions :

Restarting all services that use glibc is an essential step to protect your server.  The glibc library is widely used amongst Linux services and until the service is restarted, it will continue to use the old version.  Even if your system has had the patch installed, please ensure you restart all services using glibc, which can be made easier by simply restarting your server.

Centos 6

  1. ssh to your server using the ‘root’ credentials
  2. Once connected to your server, type:

    yum update glibc

  3. Check the version you now have installed:

    rpm -qa glibc

  4. You should see the version now installed is (or greater)

    glibc-2.12-1.166.el6_7

  5. To restart all services, we recommend that you restart your server.

shutdown -r now

Centos 7

  1. ssh to your server using the ‘root’ credentials
  2. Once connected to your server, type:

    yum update glibc

  3. Check the version you now have installed:

    rpm -qa glibc

  4. You should see the version now installed is (or greater)

    glibc-2.17-106.el7_2.4

  5. To restart all services, we recommend that you restart your server.

shutdown -r now

Ubuntu 12

  1. ssh to your server using the ‘root’ credentials
  2. Once connected to your server, type:

    apt-get install --only-upgrade libc6

  3. Check the version you now have installed:

    dpkg -l | grep libc6

  4. You should see the version now installed is (or greater)

    2.15-0ubuntu10.13

  5. To restart all services, we recommend that you restart your server.

shutdown -r now

Ubuntu 14

  1. ssh to your server using the ‘root’ credentials
  2. Once connected to your server, type:

    apt-get install --only-upgrade libc6

  3. Check the version you now have installed:

    dpkg -l | grep libc6

  4. You should see the version now installed is (or greater)

    2.19-0ubuntu6.7

  5. To restart all services, we recommend that you restart your server.

shutdown -r now