Original URL: http://www.theregister.co.uk/2011/07/27/web_application_attack_trends/

'Directory traversal' attack becomes premier hack tool

Formerly little-known method now tops rankings

By John Leyden

Posted in Security, 27th July 2011 09:21 GMT

A lesser-known attack called directory traversal is the single most commonly used technique in real-world web application attacks.

Directory traversal cropped up in 37 per cent of attacks, almost the same as cross-site scripting (36 per cent), and a fair bit ahead of SQL injection (23 per cent). Remote file inclusion figured fourth in the list of web attacks compiled by database security firm at Imperva, featuring in a comparatively small 4 per cent of assaults. Attacks are often both automated and used in combination with each other to scan for and exploit vulnerabilities.

Put crudely, directory traversal attacks rely on exploiting shortcomings in blocking attempts to access files in directories on a host computer that ought not to be accessible through web applications.

Imperva's 2011 web application attack report is based on an analysis of more than 10 million individual attacks across the internet, targeting 30 different commonly deployed enterprise-grade web applications. The study took place in the six months between December 2010 and May 2011 and included attacks witnessed via onion router (TOR) traffic.

The security firm hopes its research will help businesses to get a better handle on real-world attacks they are likely to face, helping them to develop better thought-out risk management strategies in the process.

"Most security research focuses on vulnerabilities, and while this insight is extremely valuable, it doesn’t always help businesses prioritise their security efforts," explained Amichai Shulman, lead researcher and Imperva CTO. "Take a look at the OWASP Top 10, for example. RFI and Directory Traversal were not identified as top vulnerabilities, yet our research shows that these are two of the most common attacks used by hackers to steal data."

Most of the attacks (61 per cent) detected by Imperva originated from bots within the United States, though these machines might have been controlled from anywhere. Attacks from China made up almost 10 per cent of attack traffic. The study found that 29 per cent of the attacks originated from the same 10 most active attack sources, a factor that makes blocking attacks from known bad IP addresses with a bad reputation a far more effective approach than geographical filtering.

Imperva's study can be downloaded here. ®