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USN-803-1: dhcp vulnerability

14 July 2009

dhcp vulnerability




It was discovered that the DHCP client as included in dhcp3 did not verify
the length of certain option fields when processing a response from an IPv4
dhcp server. If a user running Ubuntu 6.06 LTS or 8.04 LTS connected to a
malicious dhcp server, a remote attacker could cause a denial of service or
execute arbitrary code as the user invoking the program, typically the
'dhcp' user. For users running Ubuntu 8.10 or 9.04, a remote attacker
should only be able to cause a denial of service in the DHCP client. In
Ubuntu 9.04, attackers would also be isolated by the AppArmor dhclient3

Update instructions

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

Ubuntu 9.04
Ubuntu 8.10
Ubuntu 8.04
Ubuntu 6.06

After a standard system upgrade you need to restart any DHCP network
connections utilizing dhclient3 to effect the necessary changes.


Related notices

  • USN-803-2: dhcp3-client, dhcp3-client-udeb, dhcp-client, dhcp3