USN-3586-2: DHCP vulnerabilities

28 May 2018

isc-dhcp vulnerabilities

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

  • Ubuntu 12.04 ESM

Summary

Several security issues were fixed in DHCP.

Software Description

  • isc-dhcp - DHCP server and client

Details

USN-3586-1 fixed a vulnerability in DHCP. This update provides the corresponding update for Ubuntu 12.04 ESM.

Original advisory details:

Felix Wilhelm discovered that the DHCP client incorrectly handled certain malformed responses. A remote attacker could use this issue to cause the DHCP client to crash, resulting in a denial of service, or possibly execute arbitrary code. In the default installation, attackers would be isolated by the dhclient AppArmor profile. (CVE-2018-5732)

Felix Wilhelm discovered that the DHCP server incorrectly handled reference counting. A remote attacker could possibly use this issue to cause the DHCP server to crash, resulting in a denial of service. (CVE-2018-5733)

Update instructions

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

Ubuntu 12.04 ESM
isc-dhcp-client - 4.1.ESV-R4-0ubuntu5.13
isc-dhcp-relay - 4.1.ESV-R4-0ubuntu5.13
isc-dhcp-server - 4.1.ESV-R4-0ubuntu5.13
isc-dhcp-server-ldap - 4.1.ESV-R4-0ubuntu5.13

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

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

References