The Dangers of Default Passwords. Stroll through any neighborhood with an open laptop in hand and you will probably notice your machine automatically connecting to various wireless Internet routers that local residents have set up. If you are given a connection that allows you to surf the Web, chances are very good that you can also assume control over the same network that gave you the access.
In my experience, few people who operate wide-open wireless networks -- those unprotected by even the simplest encryption technology -- ever bother to change the default user name and password needed to reconfigure the router. Perhaps consumers who operate open networks aren't terribly worried about their neighbors "sniffing" the ambient wireless airwaves for passwords and other sensitive data. But it may be that a person running a router under the default factory settings has more to fear from a malicious Web site than a local interloper.
Researchers at Symantec Corp. have devised a series of "proof-of-concept" exploits that show how an Internet user running any one of several name-brand, $50 - $100 routers under the default factory settings could be in a world of trouble in a very short time, just by browsing to a malicious Web site. One of the easiest ways to commandeer a factory-set wireless router remotely is through the use of Javascript, a powerful Web programming language that makes it easy for Web sites to monkey with or otherwise manipulate a computer's settings.
For example, a nasty site could use Javascript to change the default settings on a router so that anytime the victim tries to visit a bank Web site he or she is silently redirected to a counterfeit site set up to steal online banking credentials (this is a type of phishing attack known as "pharming.") Or, the attackers could poke holes in the router's built-in firewall to allow certain types of traffic to slip through.
Zulfikar "Zully" Ramzan, senior principal researcher at Symantec, said he successfully tested such scenarios using mock Web pages and some of the more popular routers on the market today, including those sold by Linksys, D-Link and Netgear. "Using the same techniques, an attacker could create a very simple Web page that when viewed by a Web browser could change the default settings on a router," he said.
The reason this has the potential to be such a problem is that a broadband router sits apart from the user's computer, so it's likely to be one of those set-it-and-forget-it type appliances. Indeed, if a malicious Web site succeeded in altering the default settings on a router, the router might be the last place most users -- even security professionals -- would look to as the source of the problem.
Michael Sutton, security evangelist for Atlanta based SPI Dynamics, said Javascript's flexibility and power make it an increasingly common component of cyber attacks.
"People are always coming out with new tricks with Javascript, but the reality is that it's a very powerful language and if you can convince someone to run your code by visiting your site, you effectively control their actions," Sutton said.
So what's the takeaway here? Whether you're using a wired or wireless router to split traffic on your home network, make sure you change the default password. A comprehensive list of default usernames and passwords for just about every commercial router is already available online. If you're the forgetful type, write down your router password and store it in a safe place. Even if you don't remember it, all consumer Internet routers ship with a tiny pinhole in the back that -- with the aid of something pointy and a steady grip -- allow you to reset the router to the factory settings (and back to the default password).
Also, consider browsing the Web with Mozilla's Firefox; with it, you can use the excellent "noscript" add-on that allows you to control which sites should be permitted to run Javascript inside of the browser. It's not a perfect solution, but it has saved my bacon on more than a few occasions. If anyone is aware of a similar add-on for Internet Explorer 7, please drop a pointer to it in the comments section below. [Security Fix]
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