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The 8 most dangerous Windows vulnerabilities

The bugs that caused the most serious damage

Uncovering and exploiting Windows vulnerabilities has become as sport for many, and in a number of cases, even a career. We've rounded up a list of the worst Windows flaws we've endured since the introduction of Windows 98

That sassy bug has a lot of spunk

Bug identifier: CVE-2003-0533, MS04-011
Description: Stack-based overflow in certain Active Directory service functions in LSASRV.DLL
Alias: The Sasser bug
Date published: April 13 2004

In yet another example of ironic buffer-overflow goodness, this bug made the security subsystem of Windows the agent of evil itself. And, once again, malicious coders used Microsoft's own patch to figure out exactly where to target the OS.

As Windows XP's gatekeeper, Local Security Authority Subsystem (LSASS) manages the permissions of a PC's user accounts. So when eEye - the same company that discovered the Code Red bug - quietly disclosed the details of this flaw to Microsoft in October 2003, it touched off six months of furious coding in Redmond that culminated in a patch that fixed 13 other Windows 98, NT, 2000, XP, and Server 2003 flaws, as well as the LSASS bug.

And, within 18 days, the Sasser worm was cruising the internet, hopping from one unpatched machine to another. The poorly coded worm wreaked havoc, shutting down networks around the world. Even though a fix was already available, many users - in particular, corporate IT managers - still had not applied MS04-011. By May 1, 2004, work on fixing the unintended damage caused by Sasser had become a round-the-clock operation, says then director of the Microsoft Security Response Center, Kevin Kean, with "a number of war rooms and rotating shifts" for MSRC staffers.

Upshot: What was that about patching as soon as the updates are available? Lessons that should have been learned three years earlier didn't really sink in until Sasser publicly pummeled patchless PCs to pulp.

NEXT PAGE: Drive-by downloads

  1. These bugs caused serious damage
  2. Total server control with a single URL
  3. The Code Red bug
  4. The fastest infection ever
  5. The Blaster Worm bug
  6. The sassy bug with a lot of spunk
  7. Drive-by downloads
  8. The component that keeps on giving (headaches)

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