If you are talking about restricting "hacking" attempts across multiple services (like ssh, smtp and http) then you are beginning to move into the realm of an IDS solution (like Snort)
Currently I use denyhosts plus iptables blacklist for ssh on the servers side (plus multiple layers of firewall devices in front of the servers)... I could go with either denyhosts OR iptables, but I believe multiple methods is prudent in case one method fails
This is what my (editted) iptables listing looks like for the blacklisting
Chain INPUT (policy DROP)
target prot opt source destination
SSH tcp -- anywhere anywhere state NEW tcp dpt:ssh
Chain BLACKLIST (3 references)
target prot opt source destination
all -- anywhere anywhere recent: SET name: BLACKLIST side: source
DROP all -- anywhere anywhere
Chain SSH (1 references)
target prot opt source destination
DROP all -- anywhere anywhere recent: UPDATE seconds: 3600 hit_count: 1 name: BLACKLIST side: source
all -- anywhere anywhere recent: SET name: COUNT1 side: source
all -- anywhere anywhere recent: SET name: COUNT2 side: source
all -- anywhere anywhere recent: SET name: COUNT3 side: source
BLACKLIST all -- anywhere anywhere recent: UPDATE seconds: 60 hit_count: 5 name: COUNT1 side: source
BLACKLIST all -- anywhere anywhere recent: UPDATE seconds: 300 hit_count: 10 name: COUNT2 side: source
BLACKLIST all -- anywhere anywhere recent: UPDATE seconds: 1800 hit_count: 20 name: COUNT3 side: source
ACCEPT all -- anywhere anywhere
So if someone connects via ssh more than 5 times in one minute, 10 times in 5 minutes or 20 times in 30 minutes, they are blacklisted for an hour...
| "Neil Aggarwal"
<neil@xxxxxxxxxxxxxxxxxx>
Sent by: centos-bounces@xxxxxxxxxx 07/09/2009 09:57 AM
|
|
Hello:
I have been looking into projects that will automatically
restrict hacking attempts on my servers running CentOS 5.
I think the two top contenders are:
DenyHosts - http://denyhosts.sourceforge.net
Fail2ban - http://www.fail2ban.org
>From what I see, DenyHosts only blocks based on failed
SSH attempts whereas Fail2ban blocks failed attempts
for other access as well.
The main benefit I see from DenyHosts is their synchronization
service where my servers can proactively block hosts recognized
by other users of their service.
Does anyone have experience with these tools and have
recommendations?
Thanks,
Neil
--
Neil Aggarwal, (281)846-8957, www.JAMMConsulting.com
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a DB server failure, fiber cut, flood, fire, or other disaster?
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