Feeds

MS insists bodged fix didn't spawn Windows crash risk

Teardrop Explodes

Choosing a cloud hosting partner with confidence

Microsoft has denied claims that an unpatched flaw in a file and printer sharing feature was inadvertently introduced when it fixed an earlier, less severe problem in the software back in December 2007.

Redmond patched a medium severity flaw in the same Server Message Block (SMB) version 2 functionality within Vista nearly two years ago. Unfortunately, in the process, it allegedly created a much more serious flaw that meant systems running Vista, pre-R2 versions of Windows Server 2008, and earlier versions of Windows 7.

Vulnerable systems can be crashed with only a single malformed packet, according to Laurent Gaffié, the security researcher who discovered the so-called Teardrop attack.

Gaffié claims to have tracked back the latter problem to changes Microsoft made in resolving a flaw in SMBv2 signing nearly two years ago (via MS07-063.mspx).

"The only thing I know regarding this 'patching' process is, when they fixed this code, they opened another bigger, worse security issue," Gaffié told Security Focus.

Microsoft denied suggestions that the earlier patch might be responsible for its latest security pickle. "We researched this claim by the researcher and confirmed this vulnerability was not introduced by MS07-063," said Christopher Budd, security response communications lead for Microsoft.

Redmond earlier acknowledged that, whatever its origins, the SMB flaw is real. As well as posing a system crashing risk, the flaw also poses a code injection danger. Security researchers separately warn that the flaw could lend itself to the creation of network worms.

Pending the availability of a fix from Microsoft, users are advised to apply either apply firewall defences (Block TCP ports 139 and 445) or disable SMBv2 as possible workarounds, as explained in an advisory by the software giant here. ®

Internet Security Threat Report 2014

More from The Register

next story
FYI: OS X Yosemite's Spotlight tells Apple EVERYTHING you're looking for
It's on by default – didn't you read the small print?
Russian hackers exploit 'Sandworm' bug 'to spy on NATO, EU PCs'
Fix imminent from Microsoft for Vista, Server 2008, other stuff
Edward who? GCHQ boss dodges Snowden topic during last speech
UK spies would rather 'walk' than do 'mass surveillance'
Microsoft pulls another dodgy patch
Redmond makes a hash of hashing add-on
'LulzSec leader Aush0k' found to be naughty boy not worthy of jail
15 months home detention leaves egg on feds' faces as they grab for more power
China is ALREADY spying on Apple iCloud users, claims watchdog
Attack harvests users' info at iPhone 6 launch
Carders punch holes through Staples
Investigation launched into East Coast stores
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
Three 1TB solid state scorchers up for grabs
Big SSDs can be expensive but think big and think free because you could be the lucky winner of one of three 1TB Samsung SSD 840 EVO drives that we’re giving away worth over £300 apiece.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.