Penetration Testing mailing list archives
RE: Exploit through firewall question
From: <salexander () frontporch com>
Date: Wed, 19 Jul 2006 09:46:24 -0700
The reasons for testing behind the firewall include: 1) Firewalls can sometimes be bypassed; this is especially true of non-stateful firewalls. An attacker can use a UDP source port of 53 (DNS) or a TCP source port of 20 (the FTP data port). If the firewall allows fragments to pass, the attacker can fragment everything. 2) The attacker may gain a foothold on a publicly accessible server. New vulnerabilities are discovered every day. Even if there is no know way to compromise any of your publicly accessible services, a zero-day vulnerability could change that tomorrow. 3) Sometimes people make changes to the firewall and screw things up. At one place I worked, a vendor needed to be able to connect to one of our servers in order to troubleshoot a problem with their software. Instead of setting up a temporary VPN account or adding a temporary rule to allow the vendor to connect to a particular port from a particular network block, one of our network people added a rule that allowed open access to the box from the outside and left the rule in place after the vendor was finished. Oops. There is value in attacking from outside the firewall; it helps you to determine how hackable you are from the outside right now. But you also need to assume that an attacker will eventually find a way to gain a foothold into your network. A firewall cannot be responsible for all of your network's security. A firewall should be used to reduce the attack surface of your network. There still need to be other security measures in place behind the firewall and these measures should be assessed as well. Look up defense-in-depth. Steven -----Original Message----- From: mr.nasty () ix netcom com [mailto:mr.nasty () ix netcom com] Sent: Wednesday, July 19, 2006 6:33 AM To: pen-test () securityfocus com Subject: Re: Exploit through firewall question Thanks for the responses. You've confirmed what I had passed to mgmt. But I still have a problem (with mgmt) understanding why?... I perform vulnerability analysis on our outside (public) web presense, usually during development and then after it's been deployed. I basically use the same tools for each. Mgmt wants me to only test through the firewall as if I'm coming in like the public. The rational is that the fw will prevent any attacks though ports other than 80 and 443. Therefore, there is no reason to change this configuration. What would be the reason to test behind the firewall? Any suggestions? Thanks ------------------------------------------------------------------------ ------ This List Sponsored by: Cenzic Concerned about Web Application Security? Why not go with the #1 solution - Cenzic, the only one to win the Analyst's Choice Award from eWeek. As attacks through web applications continue to rise, you need to proactively protect your applications from hackers. Cenzic has the most comprehensive solutions to meet your application security penetration testing and vulnerability management needs. You have an option to go with a managed service (Cenzic ClickToSecure) or an enterprise software (Cenzic Hailstorm). Download FREE whitepaper on how a managed service can help you: http://www.cenzic.com/news_events/wpappsec.php And, now for a limited time we can do a FREE audit for you to confirm your results from other product. Contact us at request () cenzic com for details. ------------------------------------------------------------------------ ------ ------------------------------------------------------------------------------ This List Sponsored by: Cenzic Concerned about Web Application Security? Why not go with the #1 solution - Cenzic, the only one to win the Analyst's Choice Award from eWeek. As attacks through web applications continue to rise, you need to proactively protect your applications from hackers. Cenzic has the most comprehensive solutions to meet your application security penetration testing and vulnerability management needs. You have an option to go with a managed service (Cenzic ClickToSecure) or an enterprise software (Cenzic Hailstorm). Download FREE whitepaper on how a managed service can help you: http://www.cenzic.com/news_events/wpappsec.php And, now for a limited time we can do a FREE audit for you to confirm your results from other product. Contact us at request () cenzic com for details. ------------------------------------------------------------------------------
Current thread:
- Re: Exploit through firewall question, (continued)
- Re: Exploit through firewall question jm (Jul 19)
- Re: Exploit through firewall question Neil (Jul 19)
- Re: Exploit through firewall question Allen Pomeroy (Jul 19)
- Re: Exploit through firewall question Gary E. Miller (Jul 19)
- Re: Exploit through firewall question Larry Offley (Jul 19)
- Re: Exploit through firewall question Curt Purdy (Jul 19)
- Re: Exploit through firewall question Phil Frederick (Jul 19)
- Re: Exploit through firewall question killy (Jul 19)
- RE: Exploit through firewall question lists (Jul 19)
- Re: Exploit through firewall question R. DuFresne (Jul 20)
- RE: Exploit through firewall question salexander (Jul 19)
- RE: Exploit through firewall question Bob.Maggard (Jul 19)
- RE: Exploit through firewall question Moonen, Ralph (Jul 19)
- Re: Re: Exploit through firewall question bradcausey (Jul 19)