Cross-site Scripting (XSS)
Affecting jquery package, versions <1.9.0 >=1.7.1
Affected versions of the package are vulnerable to Cross-site Scripting (XSS) attacks. The
jQuery(strInput) function does not differentiate selectors from HTML in a reliable fashion. In the vulnerable version, jQuery determined whether the input was HTML or not by looking for the '<' character anywhere in the string, giving attackers more flexibility when attempting to construct malicious payload.
In the fixed versions, jQuery only deems the input to be HTML if it explicitly starts with '<', limiting exploitability only to attackers who can control the beginning of a string, which is far less common.
These attacks are possible by escaping the context of the web application and injecting malicious scripts in an otherwise trusted website. These scripts can introduce additional attributes (say, a "new" option in a dropdown list or a new link to a malicious site) and can potentially execute code on the clients side, unbeknown to the victim. This occurs when characters like
' are not escaped properly.
There are a few types of XSS:
- Persistent XSS is an attack in which the malicious code persists into the web app’s database.
- Reflected XSS is an which the website echoes back a portion of the request. The attacker needs to trick the user into clicking a malicious link (for instance through a phishing email or malicious JS on another page), which triggers the XSS attack.
jquery to version 1.9.0 or higher.