The bug hunt

Feature by Angela Moscoritolo

Big companies are controversially rewarding the research community to find code flaws. By Angela Moscaritolo.

Big companies are controversially rewarding the research community to find code flaws. By Angela Moscaritolo.

Standing on stage at the Facebook F8 developer's conference in September, founder and CEO Mark Zuckerberg boasted that the social media site now had more than 800 million users, and that half a billion people used it in a single day.

There is no denying that the behemoth that is Facebook has become ingrained into users' everyday lives. But even giants can fall. If members believe the information they post on the site is unsafe, they will move on – plain and simple.

This reality is not lost on those who work for the company. Within the walls of Facebook's headquarters in Palo Alto exists a culture dedicated to providing users with a secure experience, says Joe Sullivan, the company's chief security officer.

“Trust is fundamental,” Sullivan says. “That's something we think about every day. There is never a situation where the company trades off security for something else. If there is a security issue, we drop everything and deal with it.”

One of the necessities in running a web presence used by hundreds of millions of people each day is ensuring that its code is free of errors – security vulnerabilities – that could allow an attacker to gain access to private accounts. By any measure, coding errors are extremely prevalent, not just in websites, but also in commercial computing products and custom-developed systems.

“Vulnerabilities are dangerous, and people outside of the [computer security] industry aren't aware of how many latent vulnerabilities there are in products they use every day,” says Dino Dai Zovi, an independent security consultant who started bug hunting to find such issues in 1999, and who has disclosed flaws in products made by Apple and Sun Microsystems (now owned by Oracle).

While Sullivan estimates that hundreds of employees across Facebook work on security issues, there are two primary groups dedicated to preventing, finding and fixing vulnerabilities. The platform integrity team, within the software engineering department, works to ensure that every engineer in the company follows secure coding practices. Then, the product security team, which is part of the security department Sullivan manages, works to “poke holes” in the code that has been created, scouring it for vulnerabilities.

In addition to the internal bug finders, the company also calls on external auditors to review code for weaknesses before it is released online. And, to ramp up its efforts to find holes that could be abused by attackers, Facebook recently followed the lead of several other major web companies – including Google and Mozilla – to launch a so-called “bug bounty” programme. Such initiatives offer independent researchers monetary incentives for the private disclosure of vulnerabilities and exploits.

Since rolling out the programme in July 2011, Facebook has already doled out $70,000 to researchers around the world for the discreet disclosure of 72 vulnerabilities, all of which have since been fixed, Sullivan says.

“I think it is a good thing to have more people testing our site, and I believe that because we launched the programme we have encouraged more people with expertise in security issues to help us,” he says.

Landscape shifts
The bug bounty programmes represent a significant evolution in the historically fragile relationship between researchers who find security issues and companies whose products are affected. In the late 1990s and early 2000s, most large companies didn't have a defined process for dealing with reports of vulnerabilities coming in from the research community, Dai Zovi says.

“At best, they would ignore you,” he recalls. “At times, they were hostile and threatened researchers with lawsuits.”

The idea to begin paying researchers initially came from the vendor community. The first such initiatives were the Vulnerability Contributor Program, launched in 2002 by security firm iDefense (now owned by VeriSign), and the Zero Day Initiative, founded in 2005 by TippingPoint (now owned by HP). These programmes remain the top players in the commercial bug market today.

The most important shift in the vulnerability disclosure model occurred when software makers themselves started offering bug bounties, Dai Zovi says. “Vendors are switching from passively receiving reports to actively soliciting them,” he explains.

Mozilla, maker of the Firefox web browser, began such a programme in 2004. The company provides monetary rewards for the private disclosure of bugs classified as “critical,” or “high” – its most severe ratings designated for flaws that could allow an attacker to install malware without user interaction, obtain confidential data from a user's machine, or cause a denial of service requiring extensive cleanup or reinstallation of the operating system. Since launching it, Mozilla has received somewhere between 150 and 160 bounty-eligible bugs, and thousands of others lower in severity, says Brandon Sterne, a Mozilla security engineer.

Considering some companies still try to deal with security flaws internally and don't welcome bug reports from the research community, companies like Mozilla are undoubtedly ahead of the curve.

Facebook, too, has traditionally encouraged researchers to notify the company directly about security problems. “We haven't sued anyone or reported anyone to law enforcement who has reported a vulnerability to us, nor do we intend to,” Sullivan says.

In fact, the social networking site advanced its bug solicitation efforts after Sullivan's team spoke with professionals at other companies with established bug bounty programmes. Facebook now offers at least $500 for privately disclosed flaws that may “compromise the integrity or privacy of Facebook user data”. For a particularly bad flaw, the company has given $5,000.

Just two months after the project was launched, Sullivan says he is “astonished” by how effective it has been. It has enabled Facebook to build relationships with researchers from all over the world. The top two bug finders so far have been a college student from the US and an individual in Turkey, both of whom have already been paid at least five times, totalling between $5,000 and $10,000 each, Sullivan says.

Further, the bugs that are being disclosed are flaws for which the company wouldn't normally have been looking. And, the initiative has proven to be an invaluable recruitment tool.

“We had one person who asked us if they could have admission to the F8 conference instead of receiving the bounty,” Sullivan says.

“We flew them out to San Francisco and scheduled them for a series of engineering interviews the next day.”

The flip side
Bug bounty programmes have, however, been the source of controversy within the security community. Adobe does not believe that providing cash rewards in return for vulnerability details is the best way to protect its customers, says Brad Arkin, the company's senior director of product security and privacy. Doing so could cause firms to focus too much attention on offensive protections, and, as a result, neglect research investments for exploit mitigation techniques, he argues.

This imbalance “can lead to an unhealthy ecosystem where there are too many people looking for problems with too few people looking for ways to solve or defend against those problems,” Arkin says.

Tim Stanley, director of information and infrastructure security at Waste Management, a North American rubbish removal and recycling company, says he is “on the fence” about these programmes. While he doesn't totally oppose them, he says such endeavours may cause companies to expend too much of their resources fixing old software, rather than innovating for the next versions.

“Every company has a finite set of resources,” Stanley says. Time and money may be better invested in efforts to ramp up secure coding efforts, which are more proactive, he adds.

Instead of providing cash rewards for product deficiencies, Adobe invests resources to test its products for flaws, both internally and externally, by consulting with security researchers, Arkin says. But even so, the company “greatly values” the help of individuals who disclose issues in its products and credits bug finders in its security bulletins.

Mozilla's Sterne says name recognition in itself is extremely valued by security researchers, since being credited with finding a flaw in a major site or product looks good on their CV.

Still, a simple thank you can only go so far. Researchers have become disillusioned with vendors that expect them to disclose flaws for free. In 2009, a group of researchers, including Dai Zovi, started a movement called No More Free Bugs, arguing the reporting of flaws should not be pro bono.

Mozilla, for one, last July upped the price of its bug bounties from $500 to $3,000. “We realised there is a big business here,” Sterne says. “There's a lot of money being made on the black market for this type of research.”

Google quickly followed suit, raising the top reward for finding holes in its Chrome browser from $1,337 to $3,133. Since launching its vulnerability rewards programme last year, Google has paid out a total of half a million dollars.

But even with the price increases, it is often hard for researchers to make a good income from bug disclosures alone, Dai Zovi says. Such a conundrum may lead these individuals to the cyber criminal underground, where highly exploitable vulnerabilities have been sold at auction for as much as $100,000, experts say.

Selling a bug like this, however, is a different kettle of fish. “If you were a black-market security researcher discovering exploitable security bugs in software products, you would have to ‘weaponise' the exploit, which means setting it up so it is easily deployable and ready to use against consumers on the internet,” Dai Zovi says. That takes a significant amount of work, he adds.

Companies that offer bug bounties only require submitters to find a flaw and demonstrate that it is exploitable. In the end, the question of what to do with a previously undisclosed vulnerability really comes down to the individual's motivation and moral standards.

But knowing about the active black market for bugs, software vendors themselves commonly troll cyber-criminal forums looking for discussions about vulnerabilities in their products, experts say.

While vendors are, more than ever before, actively looking for bugs, some say they should be more transparent about the issues that are discovered, and provide fixes in a more timely manner. Affected vendors still sometimes wait months – even years – to remediate security issues that are privately disclosed to them, says Dan Holden, director of security research at HP TippingPoint's Digital Vaccine Laboratories.

“There is no good reason a vulnerability should take two years to patch,” Holden says. “If you know about a vulnerability, there is a high likelihood that others do as well.”

To encourage vendors to provide patches in a more timely manner, HP TippingPoint in August 2010 changed its ZDI bug bounty programme, giving affected companies a deadline to provide a fix. If a flaw isn't remediated six months after being disclosed to the vendor, ZDI publishes limited information about it, as well as mitigation information.

In addition, in 2010 Google called on companies to fix flaws within 60 days, and announced that it would publicly disclose the issues its researchers discovered if the affected company does not provide a fix within that timeframe. “Private vulnerability disclosure was, at times, allowing bugs to remain for long periods of time, even when under active exploitation,” Adam Mein, security program manager at Google, says of the company's deadline.

Such delays have, understandably, been the source of incredible frustration for researchers, as well as security professionals at end-user companies, such as Waste Management's Stanley. Users expect safe, functional products and it's up to the vendors to provide that, Stanley says.

“I suspect some companies fear that if customers know there is a problem with their product, that people won't buy it,” he adds. “I'm more likely to buy a product from a company that I know is open and transparent about the issues, because it's somebody I can trust.”

But while vendors, researchers and end-users still commonly butt heads about vulnerability issues, most can agree that the existence of flaws will be an issue for the foreseeable future, and working together to combat them is imperative.

Sullivan says Facebook is planning to expand its bug bounty programme to pre-production code, asking researchers to review code that has not yet been released. Google also says it plans to expand its list of products eligible for bug bounties.

“The security community is a really powerful, amazing group of people that is bigger than we thought,” Sullivan says. “There are lots and lots of people who care about this, if you're willing to talk about flaws. We need to have an environment where people are really open to getting better.”

Vulnerability trends: declining disclosures

During the first six months of 2011, there was a “distinct and significant decrease” in the disclosure of new vulnerabilities compared to previous years, according to HP's ‘2011 Mid-Year Top Cybersecurity Risks Report'. As of 30 June, the Open Source Vulnerability Database had recorded 3,087 flaws in internet-based systems, applications and other computing tools – about 25 per cent fewer than the 4,091 catalogued during the same period in 2010.

In fact, the reporting of new vulnerabilities has been slowly declining since 2006. On a positive note, the drop can be partly attributed to increased efforts from software makers and system developers to reduce such flaws prior to releasing their products. But even so, data collected by HP from scans of customer web application deployments shows that the actual number of flaws is not decreasing, only the number of bugs being reported.

“Production websites for some of the world's leading organisations are still bursting with vulnerabilities that leave the websites open to devastating attacks,” the report states.

The most common types of vulnerabilities being exploited in websites today are those classified as SQL injection and cross-site request forgery, both of which are web application flaws, says Dino Dai Zovi, an independent security consultant. In desktop software and mobile devices, however, memory corruption flaws are most prevalent.

This article originally appeared in the US edition of SC Magazine.


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