Re: [Full-disclosure] Gmail and China's GFW

[Cal Leeming <cal@xxxxxxxxxxxxxxxx>]

Agreed ;p

On Mon, Mar 21, 2011 at 10:19 PM, bk <chort0@xxxxxxxxx> wrote:

>
> On Mar 21, 2011, at 1:43 PM, Cal Leeming wrote:
>
>
>
> On Mon, Mar 21, 2011 at 8:39 PM, bk <chort0@xxxxxxxxx> wrote:
>
>>
>> On Mar 21, 2011, at 10:52 AM, Alien Chatter wrote:
>>
>> > $ sudo iptables -I INPUT -m string --algo bm --hex-string
>> >
>> '|476f6f676c6520496e63311830160603550403140f6d61696c2e676f6f676c652e636f6d30819f30|'
>> > -j DROP
>> >
>> > Try it, you will get a connection timeout:
>> >
>> > $ curl --connect-timeout 60 https://mail.google.com/
>> > curl: (28) SSL connection timeout
>> >
>> > The same applies for Twitter, Facebook... Much more efficient than
>> > DNS/IP blocking!
>> >
>>
>> Because searching for a bytestring in payload generates so much less load
>> than just overriding a DNS result at the recursive server (that users are
>> forced to issue queries to) or a simply drop SYNs based on IP header value
>> that routers/firewalls are optimized for...
>>
>> I think you forgot your coffee this morning.  It's not just for aliens you
>> know.
>>
>> --
>> chort
>>
>> _______________________________________________
>> Full-Disclosure - We believe in it.
>> Charter: http://lists.grok.org.uk/full-disclosure-charter.html
>> Hosted and sponsored by Secunia - http://secunia.com/
>>
>
> I think what he meant by efficient, was that if their sites ever get
> re-numbered or more end nodes are added (which may or may not be that
> often), then this would still catch the connections.
>
> Imho, I think it'd be better to just have a script checking for it, but
> nether the less, it's a cute approach (albeit, probably not usable in a
> production environment).
>
>
> It's "efficient" in that humans get to be lazy.  It's not efficient as far
> as hardware resource utilization.
>
> --
> chort
>
>
>

_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/