Feeds

MS security patch fails on local files

Not an unmitigated disaster, but you be the judge

  • alert
  • submit to reddit

The smart choice: opportunity from uncertainty

Updated The MS patch intended to fix a data binding flaw in IE, which enables a script to call executables on your Windows machine using the object tag, does not protect against malicious files launched from a local directory.

We had several anecdotal reports of trouble -- enough to cause alarm -- and went so far as to wipe a perfectly good Linux image off one of our machines and do a clean install of Win-XP. We then installed the relevant Microsoft Critical Security Update, and then ran an example script which harmlessly calls calc.exe against the machine.

We were able to run the progie without the slightest impediment from a local directory. If we hadn't tested the Critical Security Update with a live exploit, we'd never have known of its limitations.

Update

However, with further tinkering we were unable to run the script from a remote location (i.e., a Web page) or in the body of an e-mail or as an e-mail attachment once the patch was applied.

Apparently, the patch approaches the data binding issue indirectly, by restricting script permissions in the Internet zone.

We questioned whether this approach offers adequate protection, or if it's really just a partial workaround.

"The patch prevents the exploit scenario as originally presented, i.e., visiting a malicious Web site which launches an exe on your system," MS Trustworthy Computing Team Senior Security Program Manager Eric Schultze told us.

"The patch prevents what users are concerned about: they shouldn't fear to install it thinking that it doesn't fix the problem. It in fact does fix the exploit scenario."

However, it seems reasonable to imagine that that quite a few people would copy an HTML attachment to a local directory and open it if their e-mail settings prevented them from seeing what they'd received. One might well say, 'well, it's only a little Web page, after all...where's the harm in that?'  

"The patch does exactly what the bulletin makes it out to do, though whether this is the user's expectation is another matter," Schultze allows.

So I'd like to query our readers on this. E-mail me and let me know if you think the patch is adequate and we're making too much of too little here, or if you think it should be extended to the local computer zone, or even be re-worked completely to eliminate the data-binding/object-tag vulnerability altogether.

I'll post a sampling of your replies in a few days' time. ®

Securing Web Applications Made Simple and Scalable

More from The Register

next story
NO MORE ALL CAPS and other pleasures of Visual Studio 14
Unpicking a packed preview that breaks down ASP.NET
Cheer up, Nokia fans. It can start making mobes again in 18 months
The real winner of the Nokia sale is *drumroll* ... Nokia
DARPA-derived secure microkernel goes open source tomorrow
Hacker-repelling, drone-protecting code will soon be yours to tweak as you see fit
Put down that Oracle database patch: It could cost $23,000 per CPU
On-by-default INMEMORY tech a boon for developers ... as long as they can afford it
Google shows off new Chrome OS look
Athena springs full-grown from Chromium project's head
Apple: We'll unleash OS X Yosemite beta on the MASSES on 24 July
Starting today, regular fanbois will be guinea pigs, it tells Reg
HIDDEN packet sniffer spy tech in MILLIONS of iPhones, iPads – expert
Don't panic though – Apple's backdoor is not wide open to all, guru tells us
prev story

Whitepapers

Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Top 8 considerations to enable and simplify mobility
In this whitepaper learn how to successfully add mobile capabilities simply and cost effectively.
Seven Steps to Software Security
Seven practical steps you can begin to take today to secure your applications and prevent the damages a successful cyber-attack can cause.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.