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Ubuntu Security Notice USN-4365-2
May 20, 2020

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

- Ubuntu 14.04 ESM
- Ubuntu 12.04 ESM

Summary:

Several security issues were fixed in Bind.

Software Description:
- bind9: Internet Domain Name Server

Details:

USN-4365-1 fixed several vulnerabilities in Bind. This update provides
the corresponding update for Ubuntu 12.04 ESM and 14.04 ESM.
Original advisory details:

 Lior Shafir, Yehuda Afek, and Anat Bremler-Barr discovered that Bind
 incorrectly limited certain fetches. A remote attacker could possibly use
 this issue to cause Bind to consume resources, leading to a denial of
 service, or possibly use Bind to perform a reflection attack.
 (CVE-2020-8616)

 Tobias Klein discovered that Bind incorrectly handled checking TSIG
 validity. A remote attacker could use this issue to cause Bind to crash,
 resulting in a denial of service, or possibly perform other attacks.
 (CVE-2020-8617)

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+esm2

Ubuntu 12.04 ESM:
  bind9                           1:9.8.1.dfsg.P1-4ubuntu0.30

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

References:
  https://usn.ubuntu.com/4365-2
  https://usn.ubuntu.com/4365-1
  CVE-2020-8616, CVE-2020-8617