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=========================================================== Ubuntu Security Notice USN-803-1 July 14, 2009 dhcp3 vulnerability CVE-2009-0692 =========================================================== A security issue affects the following Ubuntu releases: Ubuntu 6.06 LTS Ubuntu 8.04 LTS Ubuntu 8.10 Ubuntu 9.04 This advisory also applies to the corresponding versions of Kubuntu, Edubuntu, and Xubuntu. The problem can be corrected by upgrading your system to the following package versions: Ubuntu 6.06 LTS: dhcp3-client 3.0.3-6ubuntu7.1 dhcp3-client-udeb 3.0.3-6ubuntu7.1 Ubuntu 8.04 LTS: dhcp3-client 3.0.6.dfsg-1ubuntu9.1 dhcp3-client-udeb 3.0.6.dfsg-1ubuntu9.1 Ubuntu 8.10: dhcp3-client 3.1.1-1ubuntu2.1 dhcp3-client-udeb 3.1.1-1ubuntu2.1 Ubuntu 9.04: dhcp3-client 3.1.1-5ubuntu8.1 dhcp3-client-udeb 3.1.1-5ubuntu8.1 After a standard system upgrade you need to restart any DHCP network connections utilizing dhclient3 to effect the necessary changes. Details follow: 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 profile.