brutal SSH attacks

[Vadym Chepkov]

On Feb 9, 2011, at 5:00 AM, Damien Fleuriot wrote:

> Looks like my previous message didn't make it to the list.
> 
> 
> @OP: nothing indicates that your table is getting populated correctly.
> 
> While this doesn't address your main issue, you may want to install
> sshguard which will automatically blacklist attackers and populate a
> dedicated table.
> 


Thanks for the suggestion, but as you said, it's a workaround. 
I'd rather try to understand why something that suppose to work, does not.
Because this is something I have visibility to. What if something else doesn't work as expected and I blindly trust it? 

Vadym


> 
> On 2/8/11 11:06 PM, Vadym Chepkov wrote:
>> 
>> On Feb 8, 2011, at 2:58 PM, Mike Tancsa wrote:
>> 
>>> On 2/8/2011 1:11 PM, Vadym Chepkov wrote:
>>>> Hi,
>>>> 
>>>> Could somebody help in figuring out why PF configuration meant to prevent brutal SSH attacks doesn't work.
>>>> 
>>>> Here are the relevant parts:
>>>> 
>>>> /etc/ssh/sshd_config
>>>> 
>>>> PasswordAuthentication no
>>>> MaxAuthTries 1
>>>> 
>>>> /etc/pf.conf
>>>> 
>>>> block in log on $wan_if
>>>> 
>>>> table <abusive_hosts> persist
>>>> block drop in quick from <abusive_hosts>
>>>> 
>>>> pass quick proto tcp to $wan_if port ssh keep state \
>>>> (max-src-conn 10, max-src-conn-rate 9/60, overload <abusive_hosts> flush global)
>>> 
>>> 
>>> On RELENG_7 and 8 I use something like that.  Is there a different IP
>>> they might be connecting to that is not covered under $wan_if?
>>> 
>> 
>> That would mean this rule doesn't work:
>> 
>> block in log on $wan_if
>> 
>> 
>>> 
>>> 
>>> table <bruteforce> persist
>>> table <SSHTRUSTED> {xx.yy.zz.aa}
>>> 
>>> 
>>> 
>>> block log all
>>> block in log quick proto tcp from <bruteforce> to any port 22
>>> pass in log quick proto tcp from {!<SSHTRUSTED>} to self port ssh \
>>>       flags S/SA keep state \
>>>       (max-src-conn 6, max-src-conn-rate 3/30, \
>>>       overload <bruteforce> flush global)
>>> pass in log inet proto tcp from <SSHTRUSTED> to self port ssh keep state
>>> 
>> 
>> I don't have "trusted" outside IPs, other then that your config seems the same, except mine suppose to be more strict - just one IP instead of "self".
>> By the way, wouldn't using "self" allow incoming packets to 127.0.0.1?
>> 
>> Vadym
>> 
>> 
>>> 
>>> 
>>> 	---Mike
>>> 
>>> 
>>> -- 
>>> -------------------
>>> Mike Tancsa, tel +1 519 651 3400
>>> Sentex Communications, mike at sentex.net
>>> Providing Internet services since 1994 www.sentex.net
>>> Cambridge, Ontario Canada   http://www.tancsa.com/
>> 
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