AppCheck Security Blog

In this article we’ll take a look at how the origin of resources loaded by your web application – such as third party JavaScript – can impact the security of your organisational and customer data.

A web shell is a web-based implementation of the shell concept. There’s plenty of legitimate examples where a web shell might be useful functionality – for example to provide an administrative web GUI to an appliance such as a firewall, but for the purposes of this article we will consider malicious web shells - scripts that can be uploaded by an attacker to a web server to enable remote administration of the machine unknown to the system’s proper owner.

Injection attacks are unique in that they have remained at the top of the OWASP Top 10 list since 2004. So for over a decade this type of vulnerability has been considered the most critical vulnerability for organisations to be aware of when developing code for the web.

Cross-Site Scripting or “XSS” is one of the most common vulnerabilities found in web applications. XSS made up nearly 40 per cent of all attacks logged by security researchers in recent years, who also noted that almost 75 per cent of large companies across Europe had been targeted over the last year.