A security issue has been reported in VMware ESXi, which can be exploited by malicious people to bypass certain security restrictions.

The security issue is caused due to the Update Installer incorrectly handling the SFCB authentication mode, which can lead to the SFCB authentication allowing arbitrary username and password combinations.

Successful exploitation requires that ESXi 4.1 was upgraded from ESXi 3.5 or 4.0, the SFCB configuration file (/etc/sfcb/sfcb.cfg) was modified prior to the upgrade, and that the sfcbd daemon is running (default).

The security issue is reported in version 4.1.

Solution
Install the "ESXi 4.1 Installable Update 1", which contains the patch ESXi410-201101201-SG.
Further details available to Secunia VIM customers

Provided and/or discovered by
Reported by the vendor.

Changelog
Further details available to Secunia VIM customers

Original Advisory
VMSA-2010-0020:
http://www.vmware.com/security/advisories/VMSA-2010-0020.html

VMware Knowledge Base Article #1031761:
http://kb.vmware.com/kb/1031761

Deep Links
Links available to Secunia VIM customers