An undocumented backdoor password in the Red Hat Linux Piranha package containing Linux Virtual Server (LVS) software has been discovered by Allen Wilson of the X-Force department of security outfit Internet Security Systems. The backdoor password allows remote attackers to execute commands on a server, ISS says. If an affected version of Piranha is installed and the default backdoor password remains unchanged, any remote or local user may log in to the LVS Web interface. From there, LVS parameters can be changed and arbitrary commands can be executed with the same privilege as that of the Web server. The vulnerability is present even if the LVS service is not used, ISS warns. If the affected package is installed and the password has not been changed by the administrator from the pre-set login/pass combination "piranha" and "Q", the system is vulnerable. The current distribution of Red Hat Linux 6.2 is vulnerable. Earlier versions are not. Red Hat has provided an updated Piranha package, version 0.4.13-1, available here. Meanwhile, all the gruesome technical details of the ISS advisory are posted here. ®