Feeds

Yahoo! Mail! vuln! fixed!

Buddy hacker account compromise risk plugged

  • alert
  • submit to reddit

Top 5 reasons to deploy VMware with Tegile

Yahoo! has fixed a vulnerability that left users of its popular webmail service at risk of having their login credentials stolen.

The cross-site scripting flaw, which allowed session IDs to be be stolen, involves the interaction between Yahoo! mail and the Yahoo! Messenger instant messaging client. The flaw was discovered in May by researchers at web application security firm Cenzic who worked with Yahoo! in resolving the problem.

Yahoo! fixed the vulnerability on 13 June, allowing Cenzic to publish a detailed advisory on the problem. The advisory (below) explains that miscreants would have first had to establish "buddy" status with their intended victims before carrying out the attack, which only worked were a Yahoo! mail user had configured Messenger support.

If the attacker is using the Yahoo! Messenger desktop application 8.1.0.209 to chat with the victim, and the victim is using the Messenger support in the new Yahoo! Mail Web application, it will cause a new chat tab to open in the victim’s browser. While chatting, the attacker can change their status to "invisible" causing a message of "offline" in the chat tab of the victim.

The vulnerability occurred when the attacker then changed status, and sent a custom message containing a malicious string in the form of a status message of "online", with the script executed in the context of Yahoo! Mail on the victim’s machine. This allowed an attacker to get active access to the victim’s session ID, and in turn steal their Yahoo! identity, exposing sensitive personal information stored in their Yahoo! account.

Ceznic's advisory on the vulnerability can be found here. Cross-site scripting flaws are a common class of web application vulnerability that has affected other webmail services including Gmail in the past. ®

Choosing a cloud hosting partner with confidence

More from The Register

next story
You really need to do some tech support for Aunty Agnes
Free anti-virus software, expires, stops updating and p0wns the world
Attack reveals 81 percent of Tor users but admins call for calm
Cisco Netflow a handy tool for cheapskate attackers
Privacy bods offer GOV SPY VICTIMS a FREE SPYWARE SNIFFER
Looks for gov malware that evades most antivirus
Patch NOW! Microsoft slings emergency bug fix at Windows admins
Vulnerability promotes lusers to domain overlords ... oops
Oi, Europe! Tell US feds to GTFO of our servers, say Microsoft and pals
By writing a really angry letter about how it's harming our cloud business, ta
prev story

Whitepapers

Choosing cloud Backup services
Demystify how you can address your data protection needs in your small- to medium-sized business and select the best online backup service to meet your needs.
A strategic approach to identity relationship management
ForgeRock commissioned Forrester to evaluate companies’ IAM practices and requirements when it comes to customer-facing scenarios versus employee-facing ones.
10 threats to successful enterprise endpoint backup
10 threats to a successful backup including issues with BYOD, slow backups and ineffective security.
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.
Internet Security Threat Report 2014
An overview and analysis of the year in global threat activity: identify, analyze, and provide commentary on emerging trends in the dynamic threat landscape.