Black Hat EU Cross-site scripting (XSS) vulnerabilities continue to dominate the list of most common vulnerabilities found in real-world tests.

In more than a third (37 per cent) of cases, a website vulnerable to XSS is also vulnerable to a more critical flaw such as SQL injection or improper access control, according to web security testing firm High-Tech Bridge.

Insecure WordPress blogging platform installs also continued to pose problems. More than 72 per cent of WordPress installs assessed by High-Tech Bridge had default admin panel location and at least one brute-force crackable login/password pair, nullifying any efforts their owners might have made to keep patches up to date.

More than two thirds (77 per cent) of mass website infections with malicious code are possible because of the exploitation of a known vulnerability in an open-source content management system (CMS), its plugin or theme publicly disclosed over the previous three months.

Elsewhere there has been mixed progress on the web server security front. Firms have continued to phase out the obsolete SSLv3 protocol, support for which was exploited in attacks such as POODLE (padding Oracle on downgraded legacy encryption) and others. By the end of September 18 per cent of web servers still support it, compared with 23 per cent recorded by High-Tech Bridge in June 2016.

By contrast there has been no move away from the ageing TLS 1.0 protocol: 96.1 per cent of web servers still support it, compared with 97 per cent in June 2016. Maintaining compliance with the credit card industry’s PCI DSS standard means those who handle credit card data need to drop support for TLS 1.0 from June 2018.

Ilia Kolochenko, High-Tech Bridge’s chief exec, commented: “Both SMEs and multinationals experience serious problems and face financial losses caused by insecure web applications. Traditional web security testing by automated solutions and defence by web application firewalls cannot reliably protect modern web applications any more.

“Companies shall look on DevSecOps and S-SDLC implementation to manage their web application lifecycle. Web application security is a continuous process, not an ad-hoc action or quarterly scan."

High-Tech Bridge’s web security trend findings for the year to date were announced at last week’s Black Hat EU conference. ®