Hi all, As promised, I return with the reasons I freaked when I saw what a PBX can become if used unwisely. First of all, there is the Call Fowarding - I Am Here feature, which allows you (whoever you might be) to redirect any extension to the phone you have physical access to (this is just a real life case I met.. not ANY extension, and not just any user can do that, with proper configuration). That is a very evil feature. Redirection of modem pools to my extension and the old "Login failed X 3 && cancel redirect" trick worked like a charm. Domain admin passwords were retrieved this way. Not to mention more elaborated social engineering attacks on the business processes of the company that are possible because of this. Second of all, and the most scary, I believe, is the lack of cryptographic controls on software updates for a PBX. AFAIK, there is absolutely no way the PBX can identify if changes were brought to the software update in transit, not digital signature, not even a hash (this is information confirmed upon repeated ocasions by the manufacturer's representative). This opens a door to a very dark room. We're not only talking about the usual hidden admin account, but imagine thousands of software updates being tampered with to automatically assign an extension to DISA with no authentication, bypassing the SMDR. This seems to be the case with one manufacturer, Mitel. Please tell me that I'm wrong, and please tell me that at least other manufacturers provide controls on their software updates. Also, I feel unable to come up with any sort of relevant advice on this matter. What's actually scary is the fact a PBX owner has practically no control over such an issue. He can have the most secure configuration, a relevant and enforced security policy, security conscious users, etc and he's still vulnerable. Or is he? Waiting your thoughts on this. Razvan Teslaru Romanian IT Security Company ---------------------------------------------------------------------------- This list is provided by the SecurityFocus Security Intelligence Alert (SIA) Service. For more information on SecurityFocus' SIA service which automatically alerts you to the latest security vulnerabilities please see: https://alerts.securityfocus.com/
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