The administrators of OpenSSL.org have backed off a recent charge that their site was defaced Dec. 29 by a Turkish hackers group who reached it through a compromised hypervisor.
The hypervisor that was under suspicion appears to have been VMware's ESX Server, and the charge brought a denial on Thursday from VMware, after it conducted its own investigation.
OpenSSL site administrators said Friday that the intrusion occurred instead through its hosting provider's compromised password system. That exposure gave the group, calling itself TurkGuvenligiTurkSec, temporary control of a virtualization console and allowed it to place a taunting but otherwise harmless message on the OpenSSL site. None of the site's code repositories were altered in the intrusion, an OpenSSL spokesman said in a post to the OpenSSL.org website.
OpenSSL administrators had previously said in a New Year's Day post that the attack came "via hypervisor through the hosting provider and not via any vulnerability in the OS configuration." Neither the hosting provider nor the hypervisor were named, but VMware's quick response on Jan. 2 left little doubt it was defending the integrity of its ESX Server against the OpenSSL claim.
[Want more on VMware hypervisor security? See VMware Breach: Time To Assume Hypervisor Code Open?]
"VMware is aware of suggestions that the recent defacement of the OpenSSL Foundation website may be as a result of a hypervisor compromise," a VMware spokesman said in a Jan. 2 security blog post on the VMware site.
VMware had conducted its own investigation with the OpenSSL Foundation and its service provider. "We have no reason to believe that the OpenSSL website defacement is a result of a security vulnerability in any VMware products and that the defacement is a result of an operational security error," the VMware blog said. VMware officials weren't available for further comment.
In attributing the operational security error to its hosting provider on Friday, VMware added that both had taken steps to insure there was no repeat of the incident.
Although researchers have documented theoretical examples of possible avenues of attack through a hypervisor, thus far there have been no concrete incidents of hypervisors being implemented in the field. Furthermore, security experts have shown how those theoretical attacks could be thwarted, so hypervisors have not generally been viewed as a source of exposure to the virtual machines running underneath them. Because 18 to 30 or more VMs might be managed by a single hypervisor, a corrupted hypervisor is a threat, if it materialized in operations, that could be leveraged across many virtual servers.
Ars Technica reported that the damage appears mainly to be to OpenSSL.org's pride. A Turkish hacking group left the message: "TurkGuvenligiTurkSec Was Here... we love openssl..." The last part of the message suggests the hackers were showing off skills without meaning to inflict code damage on the site.
Attackers typically try to exploit a weak or unpatched Windows or Linux operating system or a database buffer overflow, not the hypervisor. More details will be disclosed as OpenSSL proceeds with its forensics, it said.
Both the nature of the attack and sensitivity of the site meant this intrusion was going to get thoroughly reconstructed and examined. OpenSSL.org and VMware have both omitted the name of the service provider in their statements.
With growing reliance on virtualization in the datacenter and the public cloud, any hypervisor breach will draw instant attention. Dan Goodin, security editor for Ars Technica, concluded: "Users should demand a thorough autopsy. And while they're at it, they should demand the official maintainers of PHP and the Linux kernel make good on promises to provide autopsies of serious compromises on their own servers."
The public record of hypervisor operations from all vendors has so far not cited any cases of intrusion through a corrupted virtual machine system. Hypervisors are new and more difficult marks than Windows or Java. Nevertheless, as this incident points out, the intruders are getting more sophisticated, and it's inevitable that 2014 might reveal just how far attackers can go when it comes to penetrating the hypervisor.
Charles Babcock is an editor-at-large for InformationWeek, having joined the publication in 2003. He is the former editor-in-chief of Digital News, former software editor of Computerworld, and former technology editor of Interactive Week.
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