Bugtraq mailing list archives
More on the workaround for the unpatched Oracle PLSQL Gateway flaw
From: "David Litchfield" <davidl () ngssoftware com>
Date: Thu, 2 Feb 2006 18:39:44 -0000
According to Oracle, the workaround I posted, that prevents exploitation of a critical vulnerability that Oracle has so far failed to fix, breaks certain applications that sits atop their PLSQL Gateway. Though my workaround prevents exploitation of the critical flaw and thus protects vulnerable systems against attack, Oracle has made no effort to furnish me, or anyone else for that matter, with more information on how the workaround breaks some of their applications. As such, improving the workaround so it doesn't break these few applications has been mildy annoying. But I think I've tracked it down. The workaround as is
RewriteEngine on RewriteCond %{QUERY_STRING} ^.*\).*|.*%29.*$ RewriteRule ^.*$ http://127.0.0.1/denied.htm?attempted-attack RewriteRule ^.*\).*|.*%29.*$ http://127.0.0.1/denied.htm?attempted-attackwill trigger if a right facing bracket ')' appears in the PATH_INFO or _anywhere_ in the query string. Thus, if the value of a query string parameter contains a bracket the workaround will trigger. As far as the flaw is concerned, we need only concern ourselves with brackets that appear in the query string parameter name - not in the value for the parameter name. As such, if we modify the workaround to
RewriteEngine on RewriteCond %{QUERY_STRING} ^.*\).*=|.*%29.*=$ RewriteRule ^.*$ http://127.0.0.1/denied.htm?attempted-attack RewriteRule ^.*\).*|.*%29.*$ http://127.0.0.1/denied.htm?attempted-attackwe can prevent exploitation if the query string parameter name has a bracket whilst still allowing brackets it the paramter value. This can be tidied up to read
RewriteEngine on RewriteCond %{QUERY_STRING} \).*=|%29.*= RewriteRule .? http://127.0.0.1/denied.htm?attempted-attack RewriteRule \)|%29 http://127.0.0.1/denied.htm?attempted-attack # Thanks, Mike Pomraning!For those that haven't been able to adopt the workaround because it would break their specific application, then the modified workaround should work in your situation.
Cheers, David Litchfield
Current thread:
- Re: Workaround for unpatched Oracle PLSQL Gateway flaw x (Feb 01)
- More on the workaround for the unpatched Oracle PLSQL Gateway flaw David Litchfield (Feb 02)
- Re: Workaround for unpatched Oracle PLSQL Gateway flaw ad () heapoverflow com (Feb 04)
- <Possible follow-ups>
- Re: Workaround for unpatched Oracle PLSQL Gateway flaw a (Feb 08)
- Re: Workaround for unpatched Oracle PLSQL Gateway flaw David Litchfield (Feb 08)