Password-keeper LastPass plugs up IE cache leak vuln

Quis custodiet ipsos custodes?

LastPass has patched a flaw that meant Windows versions of its password-management software were capable of leaking login credentials that had been auto-filled into fields by its password manager.

The bug – which affected Internet Explorer users on Windows only – meant that an attacker who managed to obtain a memory dump of Internet Explorer would be able to extract unencrypted password strings.

"This is the same sort of attack that we have written about frequently in the context of banking malware," writes security researcher Paul Ducklin on the Sophos security blog.

Pulling off the attack would normally require either physical access to a targeted machine or an attack involving the planting of malware on a mark's PC, a level of compromise that makes most security protections redundant.

LastPass resolved the issue with a security update that also comes with a variety of performance enhancements and other tweaks. The relevant portion of the advisory explains: "Resolved: Security issue with IE exclusively while logged in to LastPass only: Prevent IE from adding passwords to in memory decryption cache".

The security fix is one of 18 items in LastPass v2.5.0/1/2, which also offers improved synchronisation and support for upcoming versions of Windows 8 and Internet Explorer 11.

The issue was first unearthed by a reader of PC Mag (story here). ®

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