Thousands of Supermicro baseboard management controllers (BMCs)
continue to spit administrator passwords in cleartext after a patch
described as unsuitable was not applied by admins.
Accessing the
machines could be dead simple for the tech savvy; vulnerable boxes would
pop during a net or Shodan scan for port 49152. Any of the roughly 3296
exposed BMCs could be accessed with the hardware's default password.
The world's worst access code – "password" – would grant access to
plenty of others.
Baseboard management controllers were an element of motherboards
that were the central component of Intelligent Platform Management
Interfaces (IPMI) which provided remote access over UDP to sysadmins for
physical state monitoring of machine fleets. Late last year, HD Moore
of metasploit fame warned
that Supermicro had a problem. Fixes seem not to have been very
effective, leaving Carinet Security Incident Response Team security
engineer Zachary Wikholm "blown away" by the Supermicro flaw.
"This
means at the point of this writing, there are 31,964 systems that have
their passwords available on the open market, Wikholm wrote on web host
Carinet's security incident response team blog.
The bungle was noted by Tony Carothers of the SANS Internet Storm Centre which verified the flaw.
"The
vulnerability involves a plaintext password file available for download
simply by connecting to the specific port, 49152," Carothers said in a handlers' note.
"One
of our team has tested this vulnerability, and it works like a champ,
so let’s add another log to the fire and spread the good word."
Admins
would need reflash their systems with a new IPMI BIOS issued by
Supermicro as a fix, but this was not possible for some admins, Wikholm
said. He offered an alternative work-around that he said did the trick
for those unable to reflash.
The Shodan scan run by the sites
proprietor John Matherly returned 9.8 million replies for HTTP GET
requests from a scattering of devices running on port 49152, many of
which ran embedded Linux platforms and broadcasted their kernel and
hardware architectures.
Some 6.4 million of these were AT&T U-Verse web media boxes and did not spew critical data.
For
the Supermicro controller subset, information on kernel versions could
be matched against Shodan to help identify embedded host information.
Many
of the total pool ran old Linux kernel versions: 23,380 operated on
2.4.31.x, 112,883 on 2.4.30.x kernel, and 710,046 systems maintained
2.4.19.x.
The news follows revelations last week that 207,000 BMCs exposed to the public internet could be exploited via a handful of basic configuration and protocol weaknesses.
Access
to BMCs permitted attackers to compromise the host server as well as
other BMCs within its management group which shared common passwords,
the researchers said at the time.
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