Abusing Cloud Services For Cybercrime

Building a botnet typically involves infecting a PC. But at the upcoming RSA Conference, two researchers plan to show how to build one with free cloud services.

Bishop Fox security researchers Oscar Salazar and Rob Ragan were able to automate the process of signing up for accounts on various cloud services, opening the door for abuse of legitimate cloud infrastructure in the name of cybercrime. It is not the first time that researchers have discussed the use of cloud platforms by attackers. Recent research (PDF) from Solutionary, for example, showed that cybercriminals are increasingly using legitimate hosting providers, such as Amazon and GoDaddy, to host malicious domains.

As cloud services have grown in popularity, so has the desire for attackers to use these services to power their attacks.

"If you look at it from a physical perspective, a criminal that uses their personal belongings in criminal acts risks confiscation of those belonging by law enforcement if caught," says Jeremy Scott, senior research analyst at Solutionary. "The same holds true in the cyberworld. Also the use of hosting services ... provides availability and redundancy that is harder to achieve on personal equipment running in your basement."

According to Ragan, he and Salazar noticed many platform-as-a-service or infrastructure-as-a-service providers offering free trials for customers. That got them thinking.

"We started getting this idea," Ragan says. "What if we could automate the process of signing up for free trials in bulk and circumvent any anti-automation that was in place?"

Many of the services -- roughly one-third of the ones they looked at -- required only email verification to create and register accounts, Ragan says. That is one of the biggest mistakes providers can make.

"It's really trivial to get a lot of email addresses and automate a process of automatically clicking confirmation links," Ragan says.

The goal of the project was to demonstrate how attackers could obtain as high a level of processing power, disk space, and network bandwidth as possible for free. In one case, they took advantage of a customer referral program offered to potential customers.

"Many cloud data storage providers offer special deals to get additional space if you refer a friend to sign up using a promo link," Ragan explains. "We automated the process of visiting that promo link and registering new accounts to create a single account that has 1 TB of storage space for free."

Some companies had other methods designed to prevent automated account creation, such as requiring credit cards, but those techniques were circumvented as well. "SMS verification can be subverted using freely available online services, such as http://www.receivesmsonline.net/, and they are actively being used for account activation if you look at the logs: http://www.receivesmsonline.net/receive-sms-online-vip-14156121873.html," he says. "Google Voice and Phone Burner are other services that provide freely available VoIP numbers that can send and receive SMS."

"Credit card verification can, in some cases, be subverted using prepaid Visa Credit cards as ... they do not even charge the account for the free trial," Ragan adds.

The situation can create myriad problems for organizations looking to block attacks, as it may be problematic to block certain services if they are critical to the business, Ragan says. In addition, it complicates attempts to gather evidence against an attacker if there is no evidence of the data they stole on their machine. In order to address this behavior, cloud providers need to improve their use of anti-automation techniques, he says.

While some of the services the researchers used have shut down their free trial programs, they are unlikely to end entirely due to businesses wanting to sign up as many users as possible, he adds.

The researchers' presentation is scheduled for Feb. 27.

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