Elefant CMS Persistent cross site scriting

Vulnerability

CVE-2017-20057 describes a persistent cross-site scripting vulnerability in the username handling of an unknown function in Elefant CMS version 1.3.12-RC [1]. The vulnerability is classified as problematic and arises because user-supplied input to the username argument is not properly sanitized before being stored or rendered, allowing an attacker to inject arbitrary HTML and JavaScript [1].

Exploitation

An attacker can exploit this vulnerability remotely without requiring authentication [1]. The attack vector involves submitting a malicious payload in the username field, which, when stored by the application and subsequently viewed by other users, executes the injected script in the context of the victim's browser session [1]. No special privileges or complex network access conditions are needed, making the attack surface accessible to any remote visitor.

Impact

Successful exploitation allows the attacker to perform actions that the victim can, such as accessing session cookies, modifying page content, or defacing the CMS [1]. Because the XSS is persistent (stored), every user who visits the affected page or function is at risk, increasing the potential reach of an attack.

Mitigation

The vendor has addressed this vulnerability in Elefant CMS version 1.3.13 [1]. Users are strongly recommended to upgrade to this or a later release to eliminate the risk. The Elefant project provides a migration path and documentation to assist administrators with the upgrade [2].