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Ubuntu Security Notice USN-4737-2
March 01, 2021

bind9 vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 14.04 ESM
- Ubuntu 12.04 ESM

Summary:

Bind could be made to crash or run programs if it received specially
crafted network traffic.

Software Description:
- bind9: Internet Domain Name Server

Details:

USN-4737-1 fixed a vulnerability in Bind. This update provides
the corresponding update for Ubuntu 12.04 ESM and Ubuntu 14.04 ESM.

Original advisory details:

 It was discovered that Bind incorrectly handled GSSAPI security policy
 negotiation. A remote attacker could use this issue to cause Bind to crash,
 resulting in a denial of service, or possibly execute arbitrary code. In
 the default installation, attackers would be isolated by the Bind AppArmor
 profile.

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 14.04 ESM:
  bind9                           1:9.9.5.dfsg-3ubuntu0.19+esm4

Ubuntu 12.04 ESM:
  bind9                           1:9.8.1.dfsg.P1-4ubuntu0.32

In general, a standard system update will make all the necessary changes.

References:
  https://usn.ubuntu.com/4737-2
  https://usn.ubuntu.com/4737-1
  CVE-2020-8625