Ubuntu 21.04: 4969-1 Critical isc-dhcp Denial of Service

ubuntu

May 27, 2021

DHCP could be made to crash if it received specially crafted network traffic.

Summary

DHCP could be made to crash if it received specially crafted network

traffic.

Software Description:

- isc-dhcp: DHCP server and client

Details:

Jon Franklin and Pawel Wieczorkiewicz discovered that DHCP incorrectly

handled lease file parsing. A remote attacker could possibly use this issue

to cause DHCP to crash, resulting in a denial of service.

Topics Covered

security advisory denial of service critical ubuntu isc-dhcp

Update Instructions

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

Ubuntu 21.04:
  isc-dhcp-client                 4.4.1-2.2ubuntu6.1
  isc-dhcp-server                 4.4.1-2.2ubuntu6.1

Ubuntu 20.10:
  isc-dhcp-client                 4.4.1-2.1ubuntu10.1
  isc-dhcp-server                 4.4.1-2.1ubuntu10.1

Ubuntu 20.04 LTS:
  isc-dhcp-client                 4.4.1-2.1ubuntu5.20.04.2
  isc-dhcp-server                 4.4.1-2.1ubuntu5.20.04.2

Ubuntu 18.04 LTS:
  isc-dhcp-client                 4.3.5-3ubuntu7.3
  isc-dhcp-server                 4.3.5-3ubuntu7.3

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