Firewall Wizards mailing list archives
Cyberguard and filtering of FTP on non-standard ports.
From: LE CORVIC Y InfoEdpEtcDep <Yoann.Le-Corvic () socgen com>
Date: Mon, 10 Mar 2003 13:50:01 +0100
Hi all, I have a question concerning filtering FTP on non standard ports. I want to allow access to an FTP server behind a Cyberguard, but this server is listening on high ports (for exemple 2021, 2020). I wanted to know if it is possible to configure this firewall to handle "intelligent filtering" of FTP communication (PORT command monitoring or PASV command pmonitoring), on ports other that 20 and 21. Any ideas would be appreciated. Thanks -----Message d'origine----- De : Paul D. Robertson [mailto:proberts () patriot net] Envoyé : lundi 10 mars 2003 04:22 À : Chuck Swiger Cc : 'firewall-wizards Objet : Re: [fw-wiz] An article from Peter Tippett/TruSecure... On Sun, 9 Mar 2003, Chuck Swiger wrote:
Date: Sun, 09 Mar 2003 13:49:08 -0500 From: Chuck Swiger <chuck () codefab com> To: 'firewall-wizards <firewall-wizards () honor icsalabs com> Subject: [fw-wiz] An article from Peter Tippett/TruSecure...
[Disclaimer: I work for TruSecure, Dr. Tippett is both our CTO and the person I report directly to. Since you didn't comment on the article, I'll take a swipe at the tradtional dogma as we tend to see it...]
http://www.globe.com/dailyglobe2/068/business/A_patch_for_IT_security_strate gy+.shtml
A brief excerpt: "For years, the focus of most security efforts has been centered on identifying and then fixing vulnerabilities in technology. The prevailing belief is that if a hole is found in the IT armor of an organization, it should be fixed immediately before it can be exploited by some cyber-deviant. While this approach sounds logical and effective, it is actually the beginning of a vicious cycle that occupies vast amounts of time and wastes several millions of corporate, government, and consumer dollars every year."
The point that Peter's making is that chasing vulnerabilities just because they exist isn't efficient, nor really achievable. There were ~2200-2400 new vulnerabilites announced last year, and as near as I can tell, between 1 and 2% of those new vulnerabilities got exploited at real companies. That means that if you spent time patching say an applicable 70% of those vulnerabilities, then 68% of that time was wasted. It's purely a risk funciton- and if you have good data on which small percentage of new vulnerabilities are going to be exploited and which ones have historically been exploited, then you can reduce your risk by about the same ammount by patching let's say 5% of those vulnerabilities instead of every one. That saves you 65% of the maintenance, fixes, "patch breaks things" and all the associated change control stuff. If you pay folks overtime, or give comp. time for staying late to patch, those can go down significantly too- *especially* if you have protections in place that limit damage from a particular vector for long enough between vulnerability disclosure, exploit coding and a normal maintenance cycle. Proactive security beats reactive security every time. Patch upon vulnerability release is reactive. Things like firewalls and conservative machine configuration can reduce patching levels for attacks from likely vectors without negatively changing an organization's risk profile. Indeed, there's an argument that if people spend more time on the likely vulnerabilities, they'll be able to better-protect an organization than if they spend time patching every possible vulnerability. I've got excellent data for widespread worms like SQL/Slammer and NIMDA, and a good feel for the results of target of choice attacks. That risks putting this too far into the "sounds like a commercial" mode though, so I'll just leave it at "smart risk-based patching beats blanket patching for effieciency with little measurable change in risk." Paul ---------------------------------------------------------------------------- - Paul D. Robertson "My statements in this message are personal opinions proberts () patriot net which may have no basis whatsoever in fact." probertson () trusecure com Director of Risk Assessment TruSecure Corporation _______________________________________________ firewall-wizards mailing list firewall-wizards () honor icsalabs com http://honor.icsalabs.com/mailman/listinfo/firewall-wizards ************************************************************************* Ce message et toutes les pièces jointes (ci-après le "message") sont confidentiels et établis à l'intention exclusive de ses destinataires. Toute utilisation ou diffusion non autorisée est interdite. Tout message électronique est susceptible d'altération. La SOCIETE GENERALE et ses filiales déclinent toute responsabilité au titre de ce message s'il a été altéré, déformé ou falsifié. ******** This message and any attachments (the "message") are confidential and intended solely for the addressees. Any unauthorised use or dissemination is prohibited. E-mails are susceptible to alteration. Neither SOCIETE GENERALE nor any of its subsidiaries or affiliates shall be liable for the message if altered, changed or falsified. ************************************************************************* _______________________________________________ firewall-wizards mailing list firewall-wizards () honor icsalabs com http://honor.icsalabs.com/mailman/listinfo/firewall-wizards
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