On 04/04/2012 10:21, Tony Mountifield wrote:
In articleCAADeyWhP3MjsPc-MO7aeWzsxsq9pHiBPHO2iU3bo8i0ttJiLcw@mail.gmail.com, Alexander Farberalexander.farber@gmail.com wrote:
Good morning
With iptables in CentOS 5 and 6 Linux - how can you please prevent processes running as "root", "apache" or "nobody" from initiating outgoing connections?
On CentOS 5 Linux I've tried putting these lines into /etc/sysconfig/iptables:
-A OUTPUT -m owner --uid-owner root -j DROP -A OUTPUT -m owner --uid-owner apache -j DROP -A OUTPUT -m owner --uid-owner nobody -j DROP
but unfortunately get the error:
# sudo service iptables restart iptables: Flushing firewall rules: [ OK ] iptables: Setting chains to policy ACCEPT: filter [ OK ] iptables: Unloading modules: [ OK ] iptables: Applying firewall rules: iptables-restore v1.4.7: owner: Bad value for "--uid-owner" option: "apache" Error occurred at line: 27 Try `iptables-restore -h' or 'iptables-restore --help' for more information. [FAILED]
Perhaps it doesn't do a username lookup and only understands numeric userids? Try:
-A OUTPUT -m owner --uid-owner 0 -j DROP -A OUTPUT -m owner --uid-owner 48 -j DROP -A OUTPUT -m owner --uid-owner 99 -j DROP
(I think those values are standard on CentOS)
Bear in mind that preventing root connections would stop you doing any kind of updating using yum, unless you have a previous rule allowing http.
Cheers Tony
This would also stop the server being able to use DNS, and would likely break other things. I'd be wary of stopping root talking out of the network.
Tris
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