On 1/12/11 5:42 AM, "Superpizza" <[email protected]> wrote:

>Hi everyone.
>I was wondering about setting up a brute force protection against a single
>client (browser).
>It happens I manage a busy site, and a I've got a bunch of customers
>coming to me through large proxies.
>This means I can't simply ban an IP
>(as dictated by current brute force rule in 2.1.1),

Are you referring to the experimental Brute Force Detection rules -
http://mod-security.svn.sourceforge.net/viewvc/mod-security/crs/trunk/exper
imental_rules/modsecurity_crs_11_brute_force.conf

If so, keep in mind that the IP collection it is using is taken from the
modsecurity_crs_10_config.conf file and the key we use is a combination of
the IP address and a hash of the User-Agent value -

#
# -=[ Global and IP Collections ]=-
#
# Create both Global and IP collections for rules to use
# There are some CRS rules that assume that these two collections
# have already been initiated.
#
SecRule REQUEST_HEADERS:User-Agent "^(.*)$"
"phase:1,t:none,pass,nolog,t:sha1,t:hexEncode,setvar:tx.ua_hash=%{matched_v
ar}"
SecAction 
"phase:1,t:none,pass,nolog,initcol:global=global,initcol:ip=%{remote_addr}_
%{tx.ua_hash}"


This should help to make the collections a bit more unique even if users
are sharing open proxies.


> but I'd like to stop a single client
>(likely a script mimicking a real browser).
>
>I thought about setting up a global collection
> populated by hashing a cookie (different value for each customer).
>Something like:
>
>SecRule REQUEST_COOKIES_NAMES:JSESSIONID "^(.*)$"

If you want to capture the "value* of the JSESSIONID, you should use -
REQUEST_COOKIES:JSESSIONID as the variable.

-Ryan

>"phase:1,t:none,pass,nolog,t:sha1,t:hexEncode,setvar: `
>tx.cookie_hash=%{matched_var}"
>
>SecAction
>"phase:1,t:none,pass,nolog,initcol:global=global,initcol: \
>ip=%{tx.cookie_hash}"
>
>I could then try to modify the rules present in
>modsecurity_crs_11_brute_force.conf to evaluate that variable.
>Any suggestion?
>
>Regards, Luca
>_______________________________________________
>Owasp-modsecurity-core-rule-set mailing list
>[email protected]
>https://lists.owasp.org/mailman/listinfo/owasp-modsecurity-core-rule-set


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