Scriptless IE Not Worth It

By Larry Seltzer  |  Posted 2004-07-05

Scriptless IE Not Worth It

The U.S. Computer Emergency Readiness Team gained a lot of attention with its advisory on the most recent Internet Explorer attack.

In the "solutions" section, it suggested—as the last of six things you might do—that you could use a different browser. Absolutely, and I wonder why the team doesnt make the same recommendation for numerous other products for which it lists vulnerabilities.

But I was more interested in the first listing in the solutions section: Disable Active scripting and ActiveX.

Disabling Active scripting and ActiveX controls in the Internet Zone—or any zone used by an attacker—appears to prevent exploitation of this vulnerability. Disabling Active scripting and ActiveX controls in the Local Machine Zone will prevent widely used payload delivery techniques from functioning.

Instructions for disabling Active scripting in the Internet Zone can be found in the CERT/CC Malicious Web Scripts FAQ. See this Microsoft Knowledge Base article for information on securing the Local Machine Zone.

Also, Service Pack 2 for Windows XP, currently in beta release, includes these and other security enhancements for IE.

Ive seen this sort of recommendation very often in past security advisories, principally in those from Microsoft. Ive always thought of it as pro-forma stuff, kind of like the potential side effects listed on a medicine package, which is basically a list of anything thats ever been observed. They have to list it, but they dont really believe in it.

Nobody would ever actually disable ActiveX controls and Active scripting, would they? I figured now was the time to try and see just how bad things were. I left related settings aside and did this only in the Internet zone.

My Internet Explorer was a lot more functional than I expected in this condition, but I still had enough problems that if I felt this was the only way to run IE, I would switch browsers myself, probably to Firefox. I dont think this is the only way to run IE, though, especially when Windows XP SP2 comes out.

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A lot of Web sites just end up looking funny, with the fonts all wrong. ESPN is one of these. I assume they are using scripting to modify the DOM. Other parts of ESPN are dysfunctional to the point of there being many empty content boxes around the screen.

Fleet Homelink, my banks site, is completely busted. I looked at the page source, and the home page has a script-based browser type and version check, so this ones a definite no-go. In cases like this, I either used a different computer (I have a lot of them), or I used Firefox.

Next Page: Seeing how other sites handle the switch.

Handling the Switch basically works, but GameDay—its live game data display—and all of the other live game things fail, unsurprisingly. Even the Java-based Yahoo GameChannel went nowhere, but I know it relies on script.

The Security Topic Center and my own blog both seem to work fine. The Ziff Davis publishing system also worked very well, although the blog administration pages failed. (Lucky for me, I mostly use NewsGators blog posting add-in.) works well, the first site Im not surprised to see do well. Slashdot has a readership that would expect such behavior. Google News also works well, but theres nothing fancy about it.

This story was inspired in part by a message I saw on a security list complaining about how Microsofts advisory pages were unreadable without scripting. Maybe they fixed it since, because the Microsoft Security page and the advisories were perfectly readable for me. Scripted elements, such as the little plus and minus symbols they use to expand and contract sections, are gone, and everything is expanded.

Not all Microsoft sites do as well. The Microsoft Knowledge Base is useless. It relies on a few listboxes and other elements that were empty. It doesnt really work in Firefox, either.

The MSDN Library, which I also use a lot, is functional, but to a much lesser degree. The big outline control on the left with the list of products and technologies is empty. You can still search.

Slate and The Wall Street Journal both work very well, although with some fancy DHTML menus disabled. On the "seriously busted" list, I put TV Guide, and The Washington Post. And while TinyURL can make the URLs, it cant put them on the clipboard.

I used to write Web programming tips, and Im sure I wrote a lot about how to do forms in script without actually writing forms. This is exactly the sort of thing that doesnt make sense anymore. If you can do something conventionally or with a less dangerous technique such as CSS, do it that way.

Finally, the administration pages for my ServGate Edgeforce Plus security appliance were unusable. Very little displays on the page. This is a problem, and Im surprised by it.

For an alternate browser, instead of the full Mozilla, I have been using Firefox for cases where I need to use scripting or Flash or whatever. Not bad at all. I had been using the full Mozilla and not liking it, but Firefox is much simpler and more familiar, which is to say its more IE-like. Its printing is not as intelligent as IEs, and I found a few other bugs, but hey, its only version 0.9.1. I could get used to this.

When things go wrong in IE, if you read security mailing lists, you can be sure to read another lecture from Thor Larholm, senior security researcher at PivX Solutions, about how its all about security zones. Internet Explorer defines several zones with different levels of privilege and puts sites in different zones based on the level of trust.

Security holes are almost always a new way for a site to escape the less-privileged zone in which it should run to get to the My Computer zone, where anything goes. The CERT advisory also talks about these problems.

PivX has a product, in free beta now, called Quik-Fix that fills these holes. Windows XP SP2 also will lock down the My Computer zone, closing off the basis for almost all of these attacks. Ill explore this whole security zones issue in more detail soon.

Its still technically too early to tell, but XP SP2 seems to be a much more viable alternative to the status quo than crazy ideas such as disabling scripting—and potentially better than running an alternate browser.

I dont want to give short shrift to Firefox, but when SP2 comes out, everyones going to need to install it anyway, so if alternate browsers lose much of their security appeal, then IE becomes more practical, too. Of course, nothing stops you from running alternate browsers on SP2.

Security Center Editor Larry Seltzer has worked in and written about the computer industry since 1983.

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