USN-3586-1: DHCP vulnerabilities

Releases

• Ubuntu 17.10
• Ubuntu 16.04 ESM
• Ubuntu 14.04 ESM

Packages

• isc-dhcp - DHCP server and client

Details

Konstantin Orekhov discovered that the DHCP server incorrectly handled a
large number of concurrent TCP sessions. A remote attacker could possibly
use this issue to cause a denial of service. This issue only affected
Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2016-2774)

It was discovered that the DHCP server incorrectly handled socket
descriptors. A remote attacker could possibly use this issue to cause a
denial of service. (CVE-2017-3144)

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 17.10

• isc-dhcp-client - 4.3.5-3ubuntu2.2
• isc-dhcp-relay - 4.3.5-3ubuntu2.2
• isc-dhcp-server - 4.3.5-3ubuntu2.2
• isc-dhcp-server-ldap - 4.3.5-3ubuntu2.2

Ubuntu 16.04

• isc-dhcp-client - 4.3.3-5ubuntu12.9
• isc-dhcp-relay - 4.3.3-5ubuntu12.9
• isc-dhcp-server - 4.3.3-5ubuntu12.9
• isc-dhcp-server-ldap - 4.3.3-5ubuntu12.9

Ubuntu 14.04

• isc-dhcp-client - 4.2.4-7ubuntu12.12
• isc-dhcp-relay - 4.2.4-7ubuntu12.12
• isc-dhcp-server - 4.2.4-7ubuntu12.12
• isc-dhcp-server-ldap - 4.2.4-7ubuntu12.12

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

References

• CVE-2016-2774
• CVE-2017-3144
• CVE-2018-5732
• CVE-2018-5733

Related notices

• USN-3586-2