Mobile workers who access the Internet from laptops while traveling can pose a serious threat to network security. That’s because laptops are more vulnerable to malicious software and hacker attacks when they are not protected by corporate security systems. When the mobile worker returns to his office and connects to the corporate network, a compromised laptop can spread malware throughout the organization or cause a company-wide security breach.
Fifteen years ago the floppy disk was the most common vector used by malware writers to spread viruses, and in more recent years email has been the primary vector. But the trend now seems toward spreading malware and exploiting vulnerabilities using malicious code on websites which exploit browser vulnerabilities. According to IBM Internet Security Systems X-Force team 2008 Trend & Risk Report “the number of vulnerabilities affecting Web applications has grown at a staggering rate. In 2008, vulnerabilities affecting Web server applications accounted for 54 percent of all vulnerability disclosures and were one of the primary factors in the overall growth of vulnerability disclosures during the year.”
To minimize the risk of succumbing to a web-borne attack then, it’s essential that laptop users use the Web as safely as possible, and the first thing to decide upon is a browser. The two most popular choices are Microsoft’s Internet Explorer and Mozilla Firefox, and there’s some debate about which one is more secure. It’s certainly true that Explorer is used by far more people than Firefox (due to it’s being part of the Windows operating system) so one could argue that, all things being equal, choosing the minority browser is the sensible choice because it offers a smaller (and thus less tempting) pool of potential victims to malware writers.
Ensuring that the browser is up to date can help minimize security risks, but perhaps the most interesting feature of Firefox from a security perspective is the possibility of enhancing the browser’s security with the addition of browser extensions or add-ons. Of course any add-ons risks adding new vulnerabilities, but if they protect against known problems at the expense of possibly adding as-yet unknown ones, then the trade-off may well be worth it.
With that proviso, here are some important ones to consider for anyone browsing the Web on a laptop outside the corporate network, to protect against web-based exploits, and more general security risks. All are available from http://addons.mozilla.org.
NoScript also protects against Cross Site Scripting attacks, and ClickJacking (also known as UI Redressing) attacks that cause users to click on buttons which are obscured by other page elements.
2. CS Lite
This simple add-on allows users to selectively or globally block cookies from websites, and view edit and delete them directly from the status bar. It does for cookies what NoScript does for scripts and plug-ins.
ShowIP helps against phishing attacks by displaying the IP address of the current website in the status bar at the bottom of the browser. While this is of limited use in itself (unless the user happens to know the IP address of the web site they want to visit,) right clicking on the IP address shown in the status bar brings up a number of options, including running a whois lookup to confirm the registered owner of the IP address concerned.
The WOT add-on gives a trustworthiness rating for sites that users visit based on feedback from other WOT users, access from a WOT button in the address toolbar. The button itself changes color depending on the trustworthiness of the site, giving an instant warning when a user visits a site that may be a source of malware. For some sites, such as those rated dangerous, WOT brings up a warning screen with the options to proceed to the site, add it to a whitelist, or to find out more information about the nature of the dangers that other users have reported.
There’s always a danger with mobile workers that bookmarks for sites that are on their desktop computers won’t be available on their laptops. If they then type in the address of the site manually there’s the possibility that they could misspell it, and end up on a malicious web site inadvertently. Foxmarks prevents this by syncing the user’s laptop and desktop bookmarks, so they can access frequently visited sites via bookmarks which are known to work. Foxmarks can also sync web site passwords (protected by a PIN) so that passwords stored on a desktop machine by Firefox’s password manager are also available without the user having to write them down for use on the road. This also makes it more practical for a user to change their passwords frequently and storethem within Firefox without having to worry about keeping the password stores on different computers synchronized.
Firefox has the ability to remember and enter passwords for web sites that the user may visit, and these passwords can be protected with a master password. If the master password is long and not guessable but stored on the user’s head (i.e. not written down) then having Firefox remember passwords can be a very secure solution. The problem is that once the master password is entered Firefox gives the user access to passwords without prompting for the master password until it detects five minutes of inactivity. This is a potential security risk if the user leaves the laptop unattended for a minute or two in a public place. To prevent this Master Password Timeout allows the user to specify their own, shorter timeout period. The master password can also be “logged off” manually from the Tools menu once Master Password Timeout is installed.
The use of encryption and digital signatures are important ways of maintaining the security of communications which are sent over insecure channels such as the Internet , when a VPN is not available. FireGPG allows users to encrypt, decrypt, sign and verify the signature of text from within Firefox from a FireGPG item in the Tools menu. It also adds buttons to the Gmail web page carrying out the same functions. Note: FireGPG requires that GnuPrivacyGuard (GPG) is installed on the laptop computer.