security question

[Chuck Swiger]

On Aug 15, 2007, at 10:08 AM, Arie Kachler wrote:
> We have many Freebsd servers with apache/php/mysql.
> Recently, some of these have been sending out large amounts of  
> emails. We know the servers are secure in the sense they are fully  
> patched. But we also know that the most secure shared server can be  
> abused by a badly written php script.

Certainly anyone with access to create new scripts can misuse the  
available resources, agreed.

> So my question is this:
> Is there a way to identify vulenrable php scripts?

I tend to assume that all PHP scripts are vulnerable, and history  
tends to support the notion that PHP has a miserable security track  
record.

> It's very difficult to pinpoint when the server starts sending out  
> emails. We just notice that they do, without any identifyable  
> correlation to anything on the logs.
>
> A related question:
> Can we audit which php script is calling sendmail?

Well, you could set up your mailserver to require that users must  
authenticate via SMTP AUTH before they are allowed to relay email.   
This would mean that the PHP scripts would need to authenticate as a  
particular user account, which would then let you see which scripts  
are generating the mail.  It would also help block malicious scripts  
which have not been setup to auth before sending the email...

-- 
-Chuck