David Litchfield releases Workaround for Unpatched Oracle Security Bug

Pete Finnigan has reported in his blog that David Litchfield has found a workaround to a critical flaw in the Oracle PL/SQL gateway. However Oracle Corporations struck-back claiming that this workaround will break several Oracle components:

http://www.petefinnigan.com/weblog/archives/00000713.htm

At 6.25pm today David Litchfield has posted a workaround for an un-patched critical flaw in the Oracle PL/SQL gateway. This is a component in iAS, OAS and the Oracle HTTP server. The bug allows an attacker to bypass the PLSQLExclusion list that stops access to critical packages and procedures. The post to the bugtraq mailing list is titled "Workaround for unpatched Oracle PLSQL Gateway flaw" and it gives details of mod_rewrite rules that can be added to the httpd.conf file. mod_rewrite is available on the platforms. The rules check for a trailing right hand bracket which is a signature of the attack.

I was aware of this issue as I had seen the NISCC post previously. Anyone who has the Oracle HTTP server enabled needs to apply this workaound immediatley.

David Litchfield posts the workaround here:

http://www.securityfocus.com/archive/1/423029

The workaround is trivial; using mod_rewrite, which is compiled into
Oracle's Apache distribution it is possible to stop the attack. The
workaround checks a user's web request for the presence of a right facing
bracket, ')'.

Add the following four lines to your http.conf file then stop and restart
the web server

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

Oracle Disagrees about the workaround

However, Oracle Corporation does not agree and claims that Litchfield’s workaround is dangerous:

http://www.networkworld.com/news/2006/012706-oracle-security.html?page=1

“Oracle is warning its customers not to use a workaround written by David Litchfield for a security vulnerability, saying the suggested workaround could break its software. Litchfield, managing director of Next Generation Security Software Ltd. in Sutton, England, said he posted the fix on the BugTraq mailing list on Wednesday after warning Oracle about the dangers the vulnerability posed. Oracle was notified of the workaround before it was released, but has found it "inadequate," said Duncan Harris, Oracle's senior director of security assurance. It will break a large number of E-Business Suite applications, he said.

"We know it will break a number of Oracle products higher in the stack than the Oracle Application Server that the vulnerability exists in," Harris said.”

Oracle goes on to criticize these security advisors, claiming that they actually perform a disservice to the Oracle community by exploiting the internals of vulnerabilities and Oracle rootkits:

"By just revealing what he has in this workaround, it definitely is a very strong starting point for any malicious hacker... to try and understand the vulnerability and produce an exploit," Harris said. "Yes, we are clearly disappointed that he felt the need to say anything about this vulnerability before we had a patch available."

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