Feeds

Exploited Hotmail bug stole email without warning

Attacks targeted email contents and contacts

Internet Security Threat Report 2014

Microsoft has patched a bug in its Hotmail email service that attackers were exploiting to silently steal confidential correspondences and user contacts from unsuspecting victims.

The vulnerability was actively being exploited using emails that contained malicious scripts, Trend Micro researcher Karl Dominguez said Monday. Successful attacks required only that a Hotmail user open the malicious email or view it in a preview window. The commands embedded in the emails uploaded users' correspondences and user contacts to servers under the control of attackers without requiring the victim to click on links or otherwise take any action.

The scripts also also had the capability of enabling email forwarding on the targeted Hotmail account, allowing attackers to view emails sent to the victim in the future.

Trend Micro researchers learned of the in-the-wild attacks after a colleague in Taiwan received one of the booby-trapped emails. The email purported to be a security warning concerning the victim's Facebook account.

Trend first disclosed the bug on May 13. Monday's blog post said Microsoft has since plugged the hole, which resided in CSS, or cascading style sheet functionality, but didn't say when.

"The attack takes advantage of a script or CSS filtering mechanism bug in Hotmail," Dominguez wrote. "Microsoft has already taken action and updated Hotmail to fix the said bug."

The vulnerable code helped inject a character into a Hotmail filtering mechanism that changed the way it behaved. The result was a platform that ran arbitrary commands in a user's Hotmail login session.

It's unclear how many Hotmail users may have been affected by the exploits and whether Microsoft has adequately warned users they may have been compromised. Microsoft spokesman Bryan Nairn wouldn't say how many subscribers were targeted or when the patch was put in place. ®

Beginner's guide to SSL certificates

Whitepapers

Driving business with continuous operational intelligence
Introducing an innovative approach offered by ExtraHop for producing continuous operational intelligence.
Why CIOs should rethink endpoint data protection in the age of mobility
Assessing trends in data protection, specifically with respect to mobile devices, BYOD, and remote employees.
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.
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.
Mitigating web security risk with SSL certificates
Web-based systems are essential tools for running business processes and delivering services to customers.