Modern web applications are typically built using a combination of in-house custom code and third-party libraries. The in-house code leverages functionality from typically open-source libraries that provide convenient access in the chosen development language to common functions (such as email sending or data structure access). These libraries will typically be deployed to the webserver serving the web application along with the in-house code… [read more]

Remote code execution (RCE) is the term used to describe the execution of arbitrary code on a system where the attacker does not have direct access to the console. Any vulnerability that allows an attacker to execute code or commands on remote system where this was not intended can be said to result in RCE.

Information disclosure occurs when out-of-scope data – such as information relating to the service operation, or its operators – is returned to clients in-band through the defined data response channel (e.g HTTP responses). Typically exploiting these vulnerabilities doesn’t require an attacker to do anything other than make passive requests (those not containing a malicious payloads) or to attempt to bypass access controls – often there is therefore no “attack signature” that can be detected in logs or blocked by Web Application Firewalls, and companies may find it impossible to prosecute an attacker or prove that they performed an action that was in any way criminal.

This article focusses on URL parsing and the security issues surrounding it, taking a look at path traversal and how this can be employed by an attacker to cause the system to read or write files outside of the intended path scope.