Malicious Spyware

September 20th, 2005

Computer SecurityI’ve been seeing a bunch of articles on a new type of spyware: keystroke loggers. A keystroke logging program will keep track of everything you type and then forward it to someone who will look for account numbers and passwords. This can be very bad when the information is for banking, credit cards, and such. A recent study found that 15% of all spyware is of the keystroke logging type.

Most of you reading this are quite tech savvy and know all about not opening attachments on incoming emails and not clicking through to web addresses given in emails (especially those purporting to be from eBay, your bank, or PayPal). But there are other ways to install malicious keystroke logging programs with which you may not be familiar.

Security Holes: Computer systems that don’t have the latest security updates are vulnerable for as long as they are connected to the internet. Malicious programs continuously scan the internet for computers with open ports to unpatched programs. Tests were run with a fresh installation of WinXP SP1, and it took approximately 4 minutes before the computer was compromised. The best way to protect against this type of attack is two-pronged: 1) Apply all patches and updates as soon as they are available, and 2) use a firewall.

Browser Vulnerabilities: Carefully crafted web pages or even web addresses can attain the ability to execute programs on your system. The best way to protect against this type of attack is to not use Internet Explorer. If you must, ensure that all of the latest patches are applied.

DNS Cache Poisoning: This is one of those cases where even if you do everything “right”, you can still be compromised. Essentially, a system that you use for DNS is given false DNS information and stores the data in its DNS cache. So when you type in www.paypal.com, for instance, you are redirected to a spoof site which gets your login/password information (and may also attempt to exploit browser vulnerabilities). The best way to protect against this type of attack is to minimize financial transactions online. In reality, you just have to trust that your ISP and upstream providers don’t let their systems get compromised—it’s really quite simple and comes down to having their DNS system correctly configured.

Internationalized Domain Names (IDN): IDN is a fairly new standard whereby non-Latin (non-English) character sets can be used in domain names. This is of greatest concern for Asian-language domains, but it was expanded to include all languages. It turns out that some languages have characters that are identical to the English language, but which are treated as different under IDN. This only works when you click through to a spoofed web site, via email or a link on another site. The best defense against an IDN attack is to use Internet Explorer 6, as it does not support the IDN standard. Other browsers, such as Firefox, have implemented security procedures to ensure the user is aware of IDN site names, but older versions do not have these measures in place and are vulnerable. More recently, researchers have found another IDN exploit in Mozilla/Firefox, and it seems like the best thing to do for now is to simply disable IDN.

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