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OS X Leopard Firewall Flawed
cycoj writes with a report in the German IT magazine Heise, taking a look at the new OS X Leopard firewall. They find it flawed. When setting access to specific services and programs to only allow SSH access, for example, they found that a manually started service was still accessible. From the article: "So the first step after starting Leopard should be to activate the firewall. The obvious choice to do so is the option to 'Set access to specific services and programs,' which promises more control over network traffic. Mac OS X automatically enters all shared resources set up by the user, such as 'Remote login' for SSH servers, into the list of accessible resources... However, initial functional testing quickly dispels any feeling of improved security. A service started for testing purposes was able to be addressed from outside without any difficulty. The firewall records this occurrence... Even with the firewall set to 'Block all incoming connections' ports to netbios, ntp and other services were still open... Specifically these results mean that users can't rely on the firewall."
Leson 1.
Never Trust Software firewalls. Software firewalls are only should be used in protection against "internet static" attacks. Where just random worms and viruses are trying to get in. Software Firewalls
Are normally bad against direct attacks from real hackers. Because there are so many ways to trick the user to install software to get around it...
Lesson 2.
Never trust anyone to keep security up. Apple, Microsoft, Linux Distributions, even Open BSD they are all made by humans and humans make mistakes and forget to check out things...
Lesson 3.
Always keep a hardware firewall even if it is a cheap Linksys Firewall/Router they will double up protection and keep your system relatively safe.
Lesson 4.
Never assume that you are 100% safe. There are always ways around things...
If something is so important that you feel the need to post it on the internet... It probably isn't that important.
most powerusers I know use Little Snitch ... its better than the firewall apple includes
"All applications shipped with Leopard are signed by Apple, and third-party software developers can also sign their applications."
"Defective by design" is not typically used to refer to "any defective technology, har har", except by a few folks here on Slashdot. "Defective by Design" is a campaign of the FSF, referring specifically devices or software that are deliberately crippled with DRM. see defectivebydesign.org.
That said, according to what I've read from some people, the security might not even be that rigorous; it might be more about making sure that only the developer of an application can update it automatically (so it's more difficult for an attacker to create an update that 'fixes' your copy of Mail.app or some other approved program to do evil things) than making sure each developer has been vetted by Apple or some other Higher Authority.
There is a posting from someone who supposedly has access to the Leopard previews over at ThinkMac basically saying this:(source)
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
Yes you are missing something.
I run all tests from a linux machine. Look at the packet dumps. It shows two machines communicating over a network.
Look at the IP address given as an argument to ntpdate -- it is a public IP of an ISP that I queried from our company network.
Look at the quoted logfile entries. All of them show that the tests have been run from external machines.
bye, ju
Which it appears to do if you look at the quote below. They show a deny in their logs. Seems to work so far.
They are now basing an assumption (or marketing spin) because of output from an Nmap scan. This just indicates a flaw in the signature Nmap has (or the lack thereof) for this particular firewall implementation.
Then straight from NMAP's documentation:
"Nmap reports the state combinations open|filtered and closed|filtered when it cannot determine which of the two states describe a port." -(http://insecure.org/nmap/man/)
And as for the NTP response being received, well that goes back to what we should expect to see. Apple is about usability. I would suspect that "Block all INCOMING connections" to not refuse information that I request. Basically this just does ingress filtering and not egress.
I haven't read the entire article yet, but from my brief scan I don't see how this is not a "functioning" firewall.
Confucius say: "Man who associates with smarter men than himself is smarter than the men he associates with."
I notice in their report that they complain about services Nmap lists as "open/filtered". Nmap reports that result when it encounters a port that elicits no reply whatsoever to a probe. This happens only when a firewall is dropping all traffic to a port and not generating any ICMP error packet for the attempt. The TCP spec says if a port isn't open the client should get an ICMP error, so Nmap knows that there's something there even if access to it's being blocked. If this is any indication of the quality of this "analysis", we can discount the article.
Actually, no, the literal definition of a firewall is a wall built to block the spread of fire, like the wall between the engine and passenger sections of a car. Not a wall made of fire, lol.