What can't a firewall protect against?
Java Security,Windows code security, Windows Server 2003 Security,Internet Explorer 7 Security and Internet Firewalls questions and answers
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What can't a firewall protect against?
Firewalls can't protect against attacks that don't go through the firewall. Many corporations that connect to the Internet are very concerned about proprietary data leaking out of the company through that route. Unfortunately for those concerned, a magnetic tape, compact disc, DVD, or USB flash drives can just as effectively be used to export data. Many organizations that are terrified (at a management level) of Internet connections have no coherent policy about how dial-in access via modems should be protected. It's silly to build a six-foot thick steel door when you live in a wooden house, but there are a lot of organizations out there buying expensive firewalls and neglecting the numerous other back-doors into their network. For a firewall to work, it must be a part of a consistent overall organizational security architecture. Firewall policies must be realistic and reflect the level of security in the entire network. For example, a site with top secret or classified data doesn't need a firewall at all: they shouldn't be hooking up to the Internet in the first place, or the systems with the really secret data should be isolated from the rest of the corporate network.
Another thing a firewall can't really protect you against is traitors or idiots inside your network. While an industrial spy might export information through your firewall, he's just as likely to export it through a telephone, FAX machine, or Compact Disc. CDs are a far more likely means for information to leak from your organization than a firewall. Firewalls also cannot protect you against stupidity. Users who reveal sensitive information over the telephone are good targets for social engineering; an attacker may be able to break into your network by completely bypassing your firewall, if he can find a ``helpful'' employee inside who can be fooled into giving access to a modem pool. Before deciding this isn't a problem in your organization, ask yourself how much trouble a contractor has getting logged into the network or how much difficulty a user who forgot his password has getting it reset. If the people on the help desk believe that every call is internal, you have a problem that can't be fixed by tightening controls on the firewalls.
Firewalls can't protect against tunneling over most application protocols to trojaned or poorly written clients. There are no magic bullets and a firewall is not an excuse to not implement software controls on internal networks or ignore host security on servers. Tunneling ``bad'' things over HTTP, SMTP, and other protocols is quite simple and trivially demonstrated. Security isn't ``fire and forget''.
Lastly, firewalls can't protect against bad things being allowed through them. For instance, many Trojan Horses use the Internet Relay Chat (IRC) protocol to allow an attacker to control a compromised internal host from a public IRC server. If you allow any internal system to connect to any external system, then your firewall will provide no protection from this vector of attack.
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Other Interview Questions
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- What are the risks?
- How common are security breaches?
- Who is at risk?
- How can I protect myself?
- What about products that claim to detect malicious applets?
- What about products that claim to block Java applets at a firewall?
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- What’s the difference between code-based security and role-based security? Which one is better?
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- #1: Default protection from potentially dangerous Active X controls
- #2: Per-zone control of Active X opt-in
- #3: Site and zone locking for Active X controls
- #4: Protection against phishing
- #5: Cross-domain security
- #6: Locked down security zones
- #7: Better SSL/TLS notification and digital certificate info
- #8: Privacy protection features
- #9: Address bars
- #10: International character alert
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- Why would I want a firewall?
- What can a firewall protect against?
- What can't a firewall protect against?
- What about viruses and other malware?
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- Where can I get more information on firewalls on the Internet?
- What are some of the basic design decisions in a firewall?
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- Network layer firewalls
- Application layer firewalls
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- What are some cheap packet screening tools?
- What are some reasonable filtering rules for a kernel-based packet screen?
- What are some reasonable filtering rules for a Cisco?
- What are the critical resources in a firewall?
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- How might I increase the security and scalability of my DMZ?
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- How can I block all of the bad stuff?
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- How do I make SSL work through the firewall?
- How do I make DNS work with a firewall?
- How do I make FTP work through my firewall?
- How do I make Telnet work through my firewall?
- How do I make Finger and whois work through my firewall?
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- How do I make RealAudio work through my firewall?
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- What is a port?
- How do I know which application uses what port?
- What are LISTENING ports?
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- What ports are safe to pass through a firewall?
- The behavior of FTP
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- Is my firewall trying to connect outside?
- The anatomy of a TCP connection
- Glossary of Firewall-Related Terms
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