Vigil@nce: ISC dhclient, shell command injection
April 2011 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/
SYNTHESIS OF THE VULNERABILITY
An attacker owning a malicious DHCP server can return a special
hostname, in order to inject a shell command in ISC dhclient.
– Severity: 2/4
– Creation date: 06/04/2011
IMPACTED PRODUCTS
– Debian Linux
– Mandriva Corporate
– Mandriva Enterprise Server
– Mandriva Linux
– OpenSUSE
– Red Hat Enterprise Linux
– Slackware Linux
– Unix - plateform
DESCRIPTION OF THE VULNERABILITY
The ISC dhclient program queries a DHCP server, in order to obtain
an IP address and a computer name.
However, a malicious or corrupted DHCP server can return a
computer name like:
beginName`command`endName
beginName;command;endName
As dhclient does not filter special shell characters, the shell
command received from the server is run on the client.
An attacker owning a malicious DHCP server can therefore return a
special hostname, in order to inject a shell command in ISC
dhclient.
This vulnerability is the same as VIGILANCE-VUL-10530
(https://vigilance.fr/tree/1/10530) which impacts dhcpcd.
ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN
http://vigilance.fr/vulnerability/ISC-dhclient-shell-command-injection-10522