In the wake of a researcher's public disclosure of flaws in Siemens products that could let an attacker take over a control system without even knowing the username and password, Siemens today said it will issue security updates in January to fix product vulnerabilities.

Security researcher Billy Rios on Tuesday posted details in his blog of some of the vulnerabilities he and fellow researcher Terry McCorkle had found and reported to the ICS-CERT and Siemens in May. Siemens confirmed it was in the process of fixing the flaws today after Rios cried foul when the company appeared to deny the existence of the vulnerabilities that he and fellow researcher Terry McCorke had been working with the company on fixing.

Rios, who says he and McCorkle have reported some 1,000 bugs in industrial control system products during the past few years, decided to go public after a Siemens PR representative told a Reuters reporter following up on Rios' work that the company had no outstanding bug reports. "I had to go public," Rios says. "I just had the PR face of a major company telling a major media outlet that I'm a BS artist."

Rios says he reported to ICS-CERT in May an authentication bypass vulnerability in Siemens Simatic systems, which manage industrial control systems, as well as several other security issues. He went public this week with the authentication bypass bug as well as two other issues: that Simatic's default password is "100," and that if a user tries to change that password using a special character (question mark, hash mark, etc.), the password automatically reverts back to "100" without the user's knowledge.

That default password was likely used by the hacker "prof," who accessed the water utility system in South Houston, Rios says. "We had reported that bug in May, and we sat on our hands and waited" for Siemens to fix it, Rios says.

Meanwhile, a Siemens spokesperson says it was all a misunderstanding: The firm had no intention of denying vulnerabilities it was working on.

Siemens today issued this statement on its website: "Siemens was notified by IT experts (Billy Rios and Terry McCorke) about vulnerabilities in some of its automation products. These are the WinCC flexible RT versions from 2004 to 2008 SP2 and WinCC Runtime Advanced V11 and multiple Simatic panels (TP, OP, MP, Comfort). We are aware of the reported vulnerabilities, first reported in May 2011. Our development had immediately taken action and addressed these issues. The vulnerabilities will be fixed by security updates, first is planned to be issued in January 2012. In December 2011 further vulnerabilities have been reported which are currently under investigation. We thank Billy Rios and Terry McCorke for reporting the vulnerabilities."

But Rios says he's still not convinced there wasn't some sort of attempt by the SCADA firm to brush under the rug its latest vulnerability woes when Siemens was contacted by the Reuters reporter. "I would have had no problem if they had said, 'We have no comment,'" Rios says. "The spirit of [the response] was deceiving."

[Researchers have been finding gaping security holes in Siemens' process control products during the past few months. See Siemens Shows Up For Black Hat Demo Of SCADA Hack.]

The most serious of the three security issues Rios revealed publicly is the authentication bypass flaw, which he shows in detail here. "Even if you set a really strong password that's not guessable, I'm able to guess access to your system anyway," he says.

When the administrator logs into the Web HMI, the application returns a session cookie that can be easily decoded to provide remote access to the Siemens Simatic HMI, according to Rios.

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