Feeds

Really critical hole in Microsoft Web software

Unchecked buffer

  • alert
  • submit to reddit

Beginner's guide to SSL certificates

ComputerWire: IT Industry Intelligence

Just one day after raising the threshold beyond which it considers security vulnerabilities "critical", Microsoft Corp released a security advisory saying there is a "critical" hole in its browsers and web servers that could cause serious problems, even if it is patched.

There is an unchecked buffer in Microsoft Data Access Components (MDAC) prior to version 2.7, the company said. MDAC is a "ubiquitous" technology used in Internet Explorer and the IIS web server. The buffer can be overrun with a malformed HTTP request, allowing arbitrary code to be executed on the target machine.

"This vulnerability is rated critical because an attacker could take over an IIS server or an Internet Explorer client and run code," Microsoft warned. "Any IIS server with MDAC and all Internet Explorer clients should apply the patch immediately."

Since Tuesday, Microsoft has defined "critical" as: "A vulnerability whose exploitation could allow the propagation of an internet worm without user action." This suggests this latest vulnerability could give rise to a virus as dangerous as Code Red, which spread to thousands of IIS servers last year.

To make matters worse, it is currently possible to make patched systems vulnerable again, Microsoft said.

Normally, when an ActiveX control is vulnerable to an attack, Microsoft's patch merely delivers a new, invulnerable control and sets a "Kill Bit" on the old one. Controls with set Kill Bits cannot be invoked by Internet Explorer. However, in this case it is not possible to set the Kill Bit without rendering countless web sites unreadable, Microsoft said.

A malicious attacker would be able to reintroduce the vulnerable control with just a specially HTML document. Users that have their browsers configured to trust Microsoft-signed ActiveX controls by default would have the vulnerability reintroduced without their knowledge.

Without a hint of irony, the company recommends removing "Microsoft" from IE's Trusted Publisher list (accessible via IE's Internet Options menu), in order to prompt a warning whenever a Microsoft-signed ActiveX control attempts to install itself. The company is working on a more permanent fix.

© ComputerWire

Protecting users from Firesheep and other Sidejacking attacks with SSL

More from The Register

next story
Spies would need SUPER POWERS to tap undersea cables
Why mess with armoured 10kV cables when land-based, and legal, snoop tools are easier?
Early result from Scots indyref vote? NAW, Jimmy - it's a SCAM
Anyone claiming to know before tomorrow is telling porkies
Apple Pay is a tidy payday for Apple with 0.15% cut, sources say
Cupertino slurps 15 cents from every $100 purchase
Israeli spies rebel over mass-snooping on innocent Palestinians
'Disciplinary treatment will be sharp and clear' vow spy-chiefs
YouTube, Amazon and Yahoo! caught in malvertising mess
Cisco says 'Kyle and Stan' attack is spreading through compromised ad networks
Hackers pop Brazil newspaper to root home routers
Step One: try default passwords. Step Two: Repeat Step One until success
China hacked US Army transport orgs TWENTY TIMES in ONE YEAR
FBI et al knew of nine hacks - but didn't tell TRANSCOM
Microsoft to patch ASP.NET mess even if you don't
We know what's good for you, because we made the mess says Redmond
NORKS ban Wi-Fi and satellite internet at embassies
Crackdown on tardy diplomatic sysadmins providing accidental unfiltered internet access
prev story

Whitepapers

Providing a secure and efficient Helpdesk
A single remote control platform for user support is be key to providing an efficient helpdesk. Retain full control over the way in which screen and keystroke data is transmitted.
WIN a very cool portable ZX Spectrum
Win a one-off portable Spectrum built by legendary hardware hacker Ben Heck
Saudi Petroleum chooses Tegile storage solution
A storage solution that addresses company growth and performance for business-critical applications of caseware archive and search along with other key operational systems.
Protecting users from Firesheep and other Sidejacking attacks with SSL
Discussing the vulnerabilities inherent in Wi-Fi networks, and how using TLS/SSL for your entire site will assure security.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.