Posted on July 26, 2013 by Richard Dominach
Recent articles in Network World, Dark Reading, Wired, and Security Week have highlighted the shocking and widespread security vulnerabilities of Baseboard Management Controllers (BMC) (and the associated Intelligent Platform Management Interface (IPMI) protocol), used for remote server management by corporations, service providers and hosting companies.
BMC’s, available from all leading server manufacturers, have direct access to the server’s motherboard. This provides the ability to monitor, boot, and even reinstall the server. Many systems provide KVM-over-IP access and the connection of remote media. Access to the BMC provides virtually unlimited remote control of the server.
Two security researchers have identified these vulnerabilities: Dan Farmer, who originally discovered and documented the vulnerabilities, and HD Moore, who describes how to identify and test for these issues, using readily available security tools. Moore discovered over 300,000 IPMI-enabled vulnerable servers connected to the Internet, as well as additional vulnerabilities.
BMC/IPMI vulnerabilities include: Cyper 0 authentication allowing access with any password, BMC-provided password hashes which can be broken via brute force methods, BMC’s shipping with enabled “anonymous” access, a UPnP vulnerability that provides root access to the BMC, and storage of clear text passwords. Once the BMC is broken into there are multiple ways to infect, control, and take over the server. Conversely, for a compromised server, the BMC can be used to establish a backdoor user account.
All server administrators and security officers need to be aware of Farmer’s and Moore’s work and understand how it affects their servers. As IPMI and BMC implementations vary, consult your server manufacturer(s). Farmer provides IPMI security best practices and Moore provides a useful FAQ.
While this research is rather new and there is much to digest, Raritan’s experts do agree that there are indeed vulnerabilities that customers should take seriously. Given the power and opacity of the BMC, this is doubly true.
Moore: “In addition to vulnerabilities in the IPMI protocol itself, most BMCs seem to suffer from issues common across all embedded devices, namely default passwords, outdated open source software, and, in some cases, backdoor accounts and static encryption keys.”
Moore: “The world of BMCs is a mess that is not likely to get better anytime soon, and we need to be crystal clear about the risk these devices pose to our networks.”
Farmer: “Imagine trying to secure a computer with a small but powerful parasitic server on its motherboard; a bloodsucker that can’t be turned off and has no documentation; you can’t login, patch, or fix problems on it; server-based defensive, audit, or anti-malware software can’t be used. Its design is secret and implementation old.”
Farmer: “It’s also the perfect spy platform: nearly invisible to its host, it can fully control the computer’s hardware and software, and it was designed for remote control and monitoring.”