Author Topic: Firewall  (Read 15262 times)

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Re: Firewall
« Reply #30 on: November 22, 2006, 05:35:08 PM »
I guess it's a case of 'do as I say' not 'do as I do' as Mastertech is a Zone Alarm user:

More like I have clients who use ZoneAlarm. I have never installed a third party Firewall on any client's computer since XP came out. Some of the most frustrating connectivity problems I've run into have been related to third party Firewalls.

Actually Frank should know better than this since I recommend ZoneAlarm on my Secure XP page for advanced users seeking more application control and logging. But I do not recommend it to make you more secure which it cannot.

Offline polonus

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Re: Firewall
« Reply #31 on: November 22, 2006, 07:32:24 PM »
Hi MT,

Question one:
So would you say that if you for instance combine Win XP firewall and for instance SafeXP settings, you have a similar protection as with ZA on a restricted user account?
Question two:
Is it still so that data can pass through the firewall, underneath the socket level, without the product (ZA) blocking or alerting users?

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Re: Firewall
« Reply #32 on: November 22, 2006, 09:45:37 PM »
1. Yes, though "Safe XP settings" are still required with ZA.

2. Once you have administrative access anything is possible.

There is a difference between recommending that people use a third party firewall to get more information about Firewall activity as opposed to irresponsibly saying the XP Firewall is insecure and they have to use a third party firewall to be secure. Especially when everyone knows that the XP Firewall provides excellent protection.

Offline Lisandro

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Re: Firewall
« Reply #33 on: November 22, 2006, 11:25:18 PM »
Some of the most frustrating connectivity problems I've run into have been related to third party Firewalls.
Isn't it a problem of configuration?  ???
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Offline FreewheelinFrank

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Re: Firewall
« Reply #34 on: November 23, 2006, 12:04:39 AM »
Once you have administrative access anything is possible.

That's what Microsoft want you to believe, since they were obliged to allow third-party firewall producers to turn off Windows firewall, this also means malware can turn it off.

Once you have administrative access anything is possible.

Firewalls like Zone Alarm at least make some attempt to protect themselves against being shut down. The results from the AV test I quoted earlier showed that ZA blocked some Trojans that Windows firewall did not. There's no guarantee that a third-party firewall will prevent malware connecting out, but it may well do so- an extra layer of protection for those who feel they want it.

Faced with somebody on the forum with an unidentified Trojan downloader, I'm never going to recommend trying to get Windows firewall back up- it's going to be a third-party firewall.

"It still isn't as robust as many third-party host-based firewalls," writes Jeff Fellinge, information security officer at media company aQuantive, in a recent analysis of the firewall.

More seriously, rival firewall makers claim that the API used to manage the Windows Firewall could also be used by attackers to modify the software or turn it off. Major firewall makers, including Zone Labs, McAfee, and Symantec are preparing SP2-compatible versions of their applications which disable Windows Firewall when they are installed, and enable it again when they are uninstalled.

But if an installer can switch off Windows Firewall, so could an attacker, argues Zone Labs, maker of the popular ZoneAlarm firewall. The company says its own products are locked down in such a way that third-party applications can't disable firewall protection without uninstalling the software.
Defining Roles

Microsoft admits that, in some cases, malicious code could indeed switch the firewall off. However, this isn't so much a flaw as a limitation on the role firewalls should play in a company's security system, according to Microsoft.

"An attacker could misuse that (administrative) capability," says David Overton, a Microsoft technical specialist. "But you're already in a compromised state, if you're at that point." He says Windows Firewall is designed to stop malicious transmissions to the PC, rather than protecting the PC once it's been infected.

If malicious code makes it past the firewall, it is the role of anti-virus software to protect the machine, Overton adds. Likewise, it is not the firewall's place to stop malicious code from sending outbound packets--Microsoft contends that companies should use perimeter technologies to examine outbound traffic.,117380-page,1/article.html
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Re: Firewall
« Reply #35 on: November 23, 2006, 12:35:07 AM »
Any Firewall can be turned off if you have adminstrator access. Even with it running all Malware has to do is wait for some trusted application to access the Internet and simply hijack the connection or process. This article explains it as clearly and logically as you can:

Windows Firewall: the best new security feature in Vista?

...any outbound host-based firewall filtering in Windows XP is really just meaningless as a security feature in my opinion. True, it stops some malware, today, but only because current malware has not been written to circumvent it. There simply are not enough environments that implement outbound rules for the mass market malware authors to need to worry about it. In an interactive attack the attacker can circumvent outbound filters at will. To see how, consider this.

Circumventing outbound host-based firewall filters can be accomplished in several ways, depending on the scenario of the actual attack. First, the vast majority of Windows XP users run as administrators, and any malware running as an administrator can disable the firewall entirely. Of course, even if the outbound filter requires interaction from the user to open a port, the malware can cause the user to be presented with a sufficiently enticing and comprehensible dialog, like this one, that explains that without clicking "Yes" they will not ever get to see the dancing pigs:

See, the problem is that when the user is running as an administrator, or the evil code runs as an administrator, there is a very good chance that either the user or the code will simply disable the protection. Of course, the user does not really see that dialog, because it is utterly meaningless to users. What the user actually processes is a dialog that looks more like this:

That is problem number one with outbound filtering. Given the choice between security and sufficiently enticing rewards, like dancing pigs, the dancing pigs will win every time. If the malware can either directly or indirectly turn of the protection, it will do so.

The second problem is that even if the user, for some inexplicable reason clicked "No. Bug me again" or if the evil code is running in using a low-privileged account, such as NetworkService, the malware can easily step right around the firewall other ways. As long as the account the code is running as can open outbound connections on any port the evil code can simply use that port. Aah, but outbound firewalls can limit outbound traffic on a particular port to specific process. Not a problem, we just piggy back on an existing process that is allowed. Only if the recipient of the traffic filters based on both source and destination port, and extremely few services do that, is this technique for bypassing the firewall meaningful.

The key problem is that most people think outbound host-based firewall filtering will keep a compromised asset from attacking other assets. This is impossible. Putting protective measures on a compromised asset and asking it not to compromise any other assets simply does not work. Protection belongs on the asset you are trying to protect, not the one you are trying to protect against! Asking the bad guys not to steal stuff after they have already broken into your house is unlikely to be nearly as effective as keeping them from breaking into the house in the first place.

In addition, as the dialogs above suggest, the vast majority of users are unable to make intelligent security decisions based on the information presented. Presenting information that does allow them to make intelligent decisions is much harder than it sounds because it would require the firewall to not just understand ports, protocols, and the application that is making the request, but also to understand what it is the request really is trying to do and what that means to the user. This information is very difficult to obtain programmatically. For instance, the fact that Microsoft Word is attempting to make an outbound connection is not nearly as interesting as what exactly Word is trying to do with that connection. A plethora of dialogs, particularly ones devoid of any information that helps an ordinary mortal make a security decision, are simply another fast clicking exercise. We need to reduce the number of meaningless dialogs, not increase them, and outbound filtering firewalls do not particularly help there. While writing this article I went and looked at the sales documentation for a major host-based firewall vendor. They tout their firewall's outbound filtering capacity and advising capability with a screen shot that says "Advice is not yet available for this program. Choose below or click More Info for assistance." Below are two buttons with the texts "Allow" and "Deny." Well, that clarifies things tremendously! My mom will surely understand what that means: "Unless you click 'Allow' below you won't get to see the naked dancing pigs that you just spent 8 minutes downloading." I rest my case.

Fundamentally, it is incumbent on the administrator to configure all outbound filtering because the end user will not be able to, and once the administrator does that, if there are enough systems using the same protection mechanism, automated malware will just adapt and exploit the weaknesses mentioned above.


Without the ability to keep a compromised process from hijacking another process outbound host-based firewall filtering provides no protection from a compromised host. Because of the fact that Service SIDs were added in Windows Vista the firewall can actually provide meaningful protection with outbound filtering, but because Windows XP inherently lacks this ability having outbound filtering on Windows XP is meaningless from a security perspective.

Now you can choose to stick your fingers in yours ears and yell as loud as Frank does running around waving his arms and calling it a big Microsoft Conspiracy or simply read and understand the information in that article.


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Re: Firewall
« Reply #36 on: November 23, 2006, 02:05:33 AM »
From the same source:

any outbound host-based firewall filtering in Windows XP is really just meaningless as a security feature in my opinion.
(emphasis added)

Isn't that all we have on this topic Mastertech?  Opinion and personal preference. 

More than once I've witnessed Zone Alarm block a trojan's outbound connection attempt.  That didn't make the computer more secure.  That doesn't mean ZA will block all malware seeking an outbound connection.  It did tell tell me there was a problem I needed to address.

But because I saw those connection attempts my personal preference is to take to a small (in my opinion) performance hit to get a some outbound protection.  Many people seem to share this sentiment but there are certainly those that share your opinion as well.  No sense letting it turn into an argument that won't change anyone's mind.


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Re: Firewall
« Reply #37 on: November 23, 2006, 04:30:48 AM »
When/if a piece of malware were to hijack a software program to bypass the firewall and get internet access a decent firewall would detect that something in the application has changed and ask the user. Firewalls such as Comodo do this.


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Re: Firewall
« Reply #38 on: November 23, 2006, 07:19:15 AM »
But there is no guarantee. Firewalls simply do simple things like path verification and process identification they have no way to know if a process has been hijacked. How hard is it for a Trojan to simply call itself Firefox.exe? It makes more sense to detect the problem BEFORE it infects you.

My problem is with people screaming that you are insecure unless you use a third party firewall and that the Windows XP firewall is not a good solution. When in reality it has excellent inbound protection, equivalent if not better than most third party firewalls.

Do I want people to uninstall their third party firewall and start using the Windows XP one? Not if you are happy with what you have. I want people to stop acting like the people who use the XP Firewall are insecure, which is nonsense.

I see security fanatics tell peope to load their systems down with so much redundant or irrelevant security software their machines run like they are infected with the Malware they are trying to prevent.


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Re: Firewall
« Reply #39 on: November 23, 2006, 08:58:45 AM »
I'm closing this, another Mastertech's-opinions-and-wishes-presented-as-facts thread.  ::)