Web servers and web-based applications are increasingly vulnerable to cross-site scripting attacks, internet security firm NTA Monitor has warned. Its research has found that attacks are beginning to appear on social networking sites and forums.
Roy Hills, technical director at NTA Monitor, said, "Attackers are creating websites in which they embed malicious code to track a visitor's searches, user names and passwords. The code can affect a visitor's PC without their knowledge and can quickly spread to other visitors' machines."
Cross-site script can occur when information submitted by users is not properly stripped of HTML tags, enabling an attacker to embed malicious code on a website, Hill said.
"When the website is accessed, the code will execute code in a user's browser. A user may be redirected to a fake website or have their log-in or user information compromised. In the worst cases, users' computers can be compromised."
It can be difficult to identify the malicious code, as browsers do not identify malware.
Hills said IT directors should ensure that staff run anti-spyware and anti-malware programs, and undertake regular penetration testing.