Personal firewalls are designed to block suspicious incoming and outgoing traffic on a client or even block an application from using the Internet altogether. It's an important job, since broadband connections are always on and, hence, easy prey for hacker programs that can sniff out their IP addresses.
But many of these personal firewalls have a design that's easy to compromise with just a few lines of code, according to several sources. In fact, to prove the point, one source sent code to eWeek with the claim that it compromised Sygate Technologies' Personal Firewall. But the source said it would work on Symantec's Norton Personal Firewall and others, as well. eWeek Labs tested the code and confirmed that it will open a back door in several personal firewalls.
Basically, the hack involves known behaviors of these products. Since the personal firewalls watch traffic based on port number and application name, all a hacker has to do is rename a virus or Trojan horse to a name that end users have likely permitted to have access to the Internet.
For example, a hacker could rename a rogue file to iexplore.exe, a file name that is not likely to be barred from using the Web. If, in fact, the end user had set his or her firewall to allow that application to access the Internet, the bad file is allowed in.
Several security experts confirmed the problem. "Everyone is on the personal firewall bandwagon, and hardly anyone is doing it right," said security expert Steve Gibson, who is building a test suite that will check for these vulnerabilities. Gibson runs his own research house, GRC.
"A Trojan comes along and calls itself a basic application like 'netscape. exe,' and they're in," he said. "And we're not talking about some future problem once the bad guys notice. These Trojans exist."
When informed of the vulnerability, Todd Baginsky, who works for Cincinnati Bell and Wireless, said, "Cool," only half-kidding.
"Hopefully, publicising this kind of hole will tighten those companies up quick," said Baginsky, Web architect and Internet security manager at Cincinnati Bell, part of Broadwing Communications. "Something this simple is scary. We have persistent connections popping up everywhere, so you don't want that to go unchecked."
When contacted about the problem, Symantec, which makes Norton Personal Firewall, confirmed it had just learned of the vulnerability.
"We were recently made aware of this, and we are looking into this as we speak," said Greg Vogel, development manager for Symantec. "Since our product includes anti-virus [capabilities], we would still catch any virus that was sent through."
Other companies declined to comment.
Gibson said that there are other problems born out of the rush to get products to market. For example, Sygate's firewall's default settings leave individual programs open to the Internet until users choose to disable access.
Symantec, in an effort to make its product more user-friendly, has a list of applications that automatically get permission to access the Internet, so users aren't even presented with the choice, Gibson said.
And some, such as BlackIce Defender, from Network Ice, don't yet offer the ability to block outgoing transmissions to the Internet from the client when the client acts as a server, according to Jose Granado, a senior manager at Ernst & Young LLP's Security Solutions Group, in Houston.
"Both points are valid. These firewalls were rushed to market and are poorly designed," said Granado, who has testified in front of the U.S. Senate about Internet security. "Version 1 of these things is not a 100 percent solution; it's like an 80 percent solution. But business is business. Everyone saw a personal firewall out there, and they all had to have one. Most of them have to get much better in their next rev."
While some of the technical vulnerabilities will likely go away in later versions of the products, there is a psychological aspect to the problem, according to Gibson and Granado. IT managers put an inherent amount of trust in security products, which actually can leave them vulnerable when the products show weaknesses such as these.
"There is this tendency, since it's security, to think, 'I can set it and forget it,'" Granado said. "That's asking for trouble. The number of telecommuters using broadband is increasing, and what I see in 2001, unfortunately, is [that] home machines will get trashed. Or they will be the dupes that allow a hacker into a corporation."
how can an ordenary person like my know if his firewall is good or bad. are there some facts which are very important? -sorry for bad english