Hack shows zero day danger

San Francisco, January 30: The recent hacking attack that prompted Google’s threat to leave China is underscoring the heightened dangers of previously undisclosed computer security flaws – and renewing debate over buying and selling information about them in the black market.

Because no fix was available, the linchpin in the attack was one of the worst kinds of security holes. Criminals treasure these types of “zero day” security vulnerabilities because they are the closest to a sure thing and virtually guarantee the success of a shrewdly crafted attack.

The attackers waltzed into victims’ computers, like burglars with a key to the back door, by exploiting such a zero day vulnerability in Microsoft Corp’s Internet Explorer browser. Microsoft rushed out a fix after learning of the attack.

How did the perpetrators learn about the flaw? Likely, they merely had to tap a thriving underground market, where a hole “wide enough to drive a truck through” can command hundreds of thousands of dollars, said Ken Silva, chief technology officer of VeriSign Inc. Such flaws can take months of full-time hacking to find.

“Zero days are the safest for attackers to use, but they’re also the hardest to find,” Silva said. “If it’s not a zero day, it’s not valuable at all.”

Valuable flaws

The Internet Explorer flaw used in the attack on Google Inc required tricking people into visiting a malicious website that installed harmful software on victims’ computers.

The attack, along with a discovery that computer hackers had tricked human-rights activists into exposing their Google e-mail accounts to outsiders, infuriated Google and provoked a larger fight over China’s censorship of the internet content.

Google has threatened to shut down its censored, Chinese-language search engine and possibly close its offices in China.

Pedram Amini, manager of the Zero Day Initiative at the security firm TippingPoint, estimated that the IE flaw could have fetched as much as $40 000. He said even more valuable zero day flaws are ones that can infect computers without any action on the users’ part.

Zero days refer to security vulnerabilities caused by programming errors that haven’t been “patched”, or fixed, by the products’ developers. Often those companies don’t know the weaknesses exist and have had zero days to work on closing the holes.

In this case, Microsoft actually knew about the flaw since September but hadn’t planned to fix it until February, as companies sometimes prioritise fixing other problems and wait on the ones they haven’t seen it used in attacks.

Microsoft often fixes multiple vulnerabilities at once because testing patches individually is time-consuming and costly, said Chris Wysopal, co-founder of security company Veracode Inc.

—Agencies