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MS Security Patch Blocks Net Access For ZoneAlarm Users
An anonymous reader writes "Users of Check Point ZoneAlarm security products, including the extremely popular, free-of-charge software firewall, have discovered that a Microsoft security update released on Tuesday has blocked their internet access. The firewall manufacturer is 'investigating the issue,' and so far the workaround seems to be to uninstall the recent DNS spoofing vulnerability fix MS08-037 (KB951748), and not reinstall it until Microsoft or Check Point have come up with updated versions of their products."
Kevin Smith on Prince
Set Zonealarm's security level to "medium".
If you're reading this article from a machine in question, you're not broken.
Now please don't call me asking if it's something you should worry about.
"It is a miracle that curiosity survives formal education." -Albert Einstein
This patch was not designed to patch a Microsoft flaw, but instead a vulnerability in nearly all implementations of DNS. So far over 100 vendors have patched their products and coordinated the release of this workaround. If zone alarm is broken because of this change they need to adjust their product to work with this change, not the other way around.
I've taken this snippet from: http://isc.sans.org/diary.html?storyid=4687 which explains things in a little more detail. Full details won't be disclosed until Blackhat in vegas this August.
The root cause is a fundamental, well known, weakness in the DNS protocol. DNS uses UDP, a stateless protocol. A DNS server will send a request in a single UDP packet, then wait for a response to come back. In order to match request and response, a number of parameters are checked:
who sent the response? Was it the DNS server we sent the request to?
for this particular response, do we have an outstanding request?
each request uses a unique and random query ID. The response has to use the same query ID.
The response has to be sent to the same port from which the request was sent.
Only if all this matches, the response is accepted. The first valid response wins. If an attacker is able to guess the query id and the source port, the attacker is able to send a fake response, which will be cached by the DNS server.
Remember that you are unique, just like everybody else.
Why not take this time to try out something new?
But this is Slashdot.. ofcource it is Microsoft's fault.
Why are we assuming that this is a defect in the Microsoft patch, rather than a defect in the security software? I think it's much more likely that the software firewall application (which tend to be pretty skeevy in general, see Norton Internet Security) is inappropriately blocking access than that Microsoft screwed up the patch. From my (admittedly vague) understanding of the issue, I'm guessing that the firewall software whitelists outgoing UDP requests from port 53, and the new randomized ports are being blocked, preventing DNS queries from succeeding. I know blaming Microsoft is fun, but blaming even crappier software vendors is more fun :)
Microsoft should have tested this security update with all the popular firewall software and notified the developers of the firewall software itself. Then Microsoft and the affected software companies should have sent a notification of this issue to registered users of their software.
Zone Alarm certainly counts as popular firewall software
If Microsoft did not test this against zone alarm , than that is pretty shabby QA on the part of Microsoft. If they did, and did not find the issue than it is still pretty shabby QA.
If this was tested and the makers of the software notified, than it was pretty bad on the part of both Microsoft and the third party developers not to notify users and ISPs of this impending issue.
Basically, this surprise for ISP's and users never should have occurred.
We have a Cisco ASA at work for a large enterprise and about 2 hours after I applied the patch to our DNS servers running BIND, they the ASA device blackholed the DNS servers. Wasn't a fun day really.
Ahh the great security blanket called the software firewall. I like to use the following analogy in regards to them. Having a software firewall on your computer is like having a security guard in your bathroom. If something gets to the guard it's too late, your network is already compromised.
I work for an ISP in Tacoma WA, and Software firewalls cause many more problems then they solve. I don't care which company makes it.
If you are really concerned about security then you will have a dedicated hardware firewall. These are inexpensive and common, even built into most SOHO routers.
So I know there will probably be flames, but if you write software firewalls, remember that the overwhelming majority of people who use them don't usually know they have one, and just ignore those little messages and click allow on everything until they actually read something and say "msimn.exe, what's that? I'm gonna block it!" And then they call me because their e-mail doesn't work.
I'm a happy pessimist. I expect and prepare for the worst, when it doesn't happen I am pleasantly surprised.
Microsoft starts new ad campaign about how great Vista is now and XP suddenly fails. Good one, Balmer.
...or instead of complaining to Microsoft, you can disable ZoneAlarm and enjoy having your connection work again. Cheap firewalls failing to perform exactly how you'd like them to is an old, old story.
Given the ridiculous profusion of budget 'security' software swarming around, it hardly seems fair to lay the blame on M$ when ZoneAlarm is the only program that this patch appears to conflict with.
Of course, if ZoneAlarm wasn't proprietary, we could go see where they screwed up. Maybe you should go harass them for being closed-source instead?
"We have to go forth and crush every world view that doesn't believe in tolerance and free speech." - David Brin
And what do Slashdot readers have to say? In about equal numbers:
OK geniuses. What, realistically, is the industry supposed to do in order to stop doing this sort of thing?
I don't know what the answer is. If I did, I'd be lining up staffing, capital, etc. But I'm 100% sure that it is not:
You can't see ANYTHING from a car, You've got to get out of the goddamned contraption and walk...Edward Abbey
...or instead of complaining to Microsoft, you can disable ZoneAlarm and enjoy having your connection work again.
Touché. I'd mod you up. Anyway, now that you mention it... the point of zonealarm is that the default firewall that comes with Windows is terribly insecure. It's interesting how a proprietary OS ends up spawning a lot of proprietary firewall and antivirus software.
My point? No point, it's just interesting to see how proprietary spawns proprietary... as if they were living beings.
Don't worry. Removing the patch was easy once I knew that was what needed to be done. Just go to Add/Remove Programs, check the box for "Show updates", scroll down to KB951748, click the Remove button, and reboot (again).
The may be a big headache for somebody at an ISP who needs to help out users, but as somebody who uses ZoneAlarm, I find it to be very useful.
I've got an actual firewall in my router, but that only protects me from what comes in. And I run Linux, so that counters most other random garbage. But, on occasion, I use Windows and ZoneAlarm is very handy because it alerts me when any program is trying to send data out.
*This* is where software firewalls in Windows shine. So many programs in Windows phone home or access the Internet for completely unknown reasons. So, I block it. If it breaks and I really need that particular program, I can unblock it. It's hard to measure how much this really helps, and, of course, I'm sure there are ways to transmit in Windows without the firewall knowing about it. Still, it's nice to be able to say apps X and Y, you get to access the Net. Everybody else has to ask first.
Elrond, Duke of URL
"This is the most fun I've had without being drenched in the blood of my enemies!"-Sam&Max
It's bad if an *outbound* software firewall is your ONLY form of defence. But it is an INBOUND firewall too and it does a damn good job of that, considering. I've had people back in the dial-up / USB broadband modem days who used it exclusively as a defence and there were no problems at all. They frequently got attack probes aimed at them and they all bounced off harmlessly. For five minutes work and a free download, it's much better value for money than trying to put a hardware firewall into computer novice's homes, with their 56k's and Speedtouch's.
But its main use is to turn off things that ask for the Internet that cannot be otherwise turned off, and does so without requiring TCP port rules etc. It also alerts even the knowledgeable user to strange Internet requests ("Opera is acting as a server"... is it? Why? Oh, I've hit an IRC address and it's trying to act as an IDENT server). If I could afford it, I'd put it on every Windows PC in the schools I work in (if I could move them off Windows, I would do that too) - it has an especially nice, centrally-configured network version so you can stop ANY program on ANY client that does happen to get executed from accessing the network/Internet unless it's on your whitelist - perfect for stopping a virus outbreak in its tracks.
Most importantly, however, it's fantastic as a basic Windows firewall for places where YOU CAN'T GET HARDWARE FIREWALLS. Say you have a wireless laptop that connects through your home network (a not-unusual scenario). The laptop is protected against Internet-based attacks but not against local wireless-based ones. So you either have to 1) rely on your wireless to be perfectly secure for the course of its life (WEP should have taught you that that is a silly thing to do), 2) Provide a hardware firewall on the laptop itself (means carrying another gadget like that USB stick that is a Linux firewall), 3) Using a VPN (which means forcing its use for everything Windows tries to transmit) or 4) using a software firewall. Zonealarm happens to be great at 3 AND 4.
For example, I have the following setup:
Windows laptop with wireless
Wireless access point
PC in the house with wireless card and OpenVPN
Internal network
Broadband connection
Everything past the Windows laptop is Linux and locked down (and I have Linux on a laptop to that connects in the same way). In my case, I use Zonealarm on the Windows laptop to MAKE SURE that nothing gets out across the (secured with WPA2) wireless connection except OpenVPN packets. This FORCES Windows to use OpenVPN (which it likes to avoid whenever possible, i.e. I plug another Ethernet interface into it and it changes routes etc.) for everything. I have an "insecure" network running behind the LAN but the only transit across it is via a secured VPN.
Without Zonealarm, you get hundreds of DNS, Samba, etc. requests coming out of the laptop, flying across the wireless, affecting speed, bandwidth and (potentially) security of the network. With a decent software firewall on Windows (or a decent TCP outbound firewall on Linux), I'm able to make sure that NOTHING but OpenVPN can talk to the wireless network - I could even turn off the wireless points encryption (or it be compromised, or obsoleted, or removed for incompatibility/speed/bandwidth/latency reasons) and it wouldn't matter because nothing but OpenVPN can talk out.
Without ZoneAlarm, Windows is VERY chatty on any external network, plus it's difficult (but not impossible) to make it use only ONE route (your OpenVPN tunnel) out of many possible routes without something like ZoneAlarm, especially if things change often (e.g. you put a second wireless card in, or plug in an Ethernet card etc.). I also found that Windows Firewall was absolutely useless for this, and presented problems using OpenVPN in the particular mode I wanted it to (UDP I think, but it's been a while since I've had to touch any config files for that).
With Windows Firewall, OpenVPN connections died before they could complete