A novel technique based on MapReduce could let hackers hijack computing resources used by cloud-based mobile browsers and use them anonymously, according to security researchers from North Carolina State University and the University of Oregon.

Cloud browsing uses outside computing power to process web pages and deliver them to end users, instead of doing the heavy lifting on the end-user's own device. The researchers say that the technique is particularly useful for mobile browsing, which would otherwise have to rely on a mobile device's less-powerful hardware. Opera Mini and Android Silk are the best-known browsers to use the technique, though there are others available.

However, the clouds used to do the heavy lifting can be tricked into doing a number of other things, according to the researchers, who have written a paper on the subject. They call the technique browser MapReduce or BMR.

The team tested its idea by storing pieces of data on URL shortening sites, effectively tricking both those sites and the cloud browser providers into performing computations for them. NCSU assistant professor William Enck, a co-author of the paper, said in a statement that the team limited the amount of data processed in this way to 100MB.

"It could have been much larger, but we did not want to be an undue burden on any of the free services we were using," he said.

Used maliciously, Enck added, the technique could provide hackers with vast, temporary and completely anonymous computing horsepower, allowing them to crack passwords or perform other nefarious tasks at great speed.

Depending on the scale of the attack, users may not notice anything is going on, he said.

"It depends on how well-provisioned the cloud browser platform is, as well as how large of a job the attacker is executing. Cloud browsers operators who are monitoring resource use will definitely notice a spike in service use. However, reacting to BMR jobs requires the operator to build additional defenses into their framework," Enck said.