# Ping Identity Agentless Integration Kit Reflected Cross-site Scripting (XSS) # Link: https://github.com/sbaresearch/advisories/tree/public/2019/SBA-ADV-20190305-01_Ping_Identity_Agentless_Integration_Kit_Reflected_XSS ## Vulnerability Overview ## Ping Identity Agentless Integration Kit before 1.5 is susceptible to Reflected Cross-site Scripting at the `/as/authorization.oauth2` endpoint due to improper encoding of an arbitrarily submitted HTTP GET parameter name. * **Identifier** : SBA-ADV-20190305-01 * **Type of Vulnerability** : Cross-site Scripting * **Software/Product Name** : [Ping Identity Agentless Integration Kit](https://www.pingidentity.com/developer/en/resources/agentless-integration-kit-developers-guide.html) * **Vendor** : [Ping Identity](https://www.pingidentity.com/) * **Affected Versions** : < 1.5 * **Fixed in Version** : 1.5 * **CVE ID** : CVE-2019-13564 * **CVSSv3 Vector** : AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N * **CVSSv3 Base Score** : 6.1 (Medium) ## Vendor Description ## > After authenticating the user (via a federated security token or > authentication adapter), the user will be presented to the protected > application via an SP adapter. This adapter provides the last-mile > connection between the federation server (PingFederate) and the > application, the user will be presented to the application which can > then create a session and render the application for the > authenticated user. Source: <https://www.pingidentity.com/developer/en/resources/agentless-integration-kit-developers-guide/last-mile-integration.html> ## Impact ## By exploiting the documented vulnerability, an attacker can execute JavaScript code in a victim's browser within the origin of the target site. This can be misused, for example, for phishing attacks by displaying a fake login form in the context of the trusted site via JavaScript and then sending the victim's credentials to the attacker. ## Vulnerability Description ## The `/as/authorization.oauth2` endpoint of PingFederate takes several HTTP GET parameter name-value pairs, which are subsequently rendered as an HTML form with hidden input fields. ```text https://idp.example.com/as/authorization.oauth2?response_type=code&client_id=CLIENT&redirect_uri=https%3A%2F%2Fapp.example.com%2Fcb ``` The name of the HTTP parameter is rendered as the `name` attribute of the corresponding input field, and the HTTP parameter value is rendered as the `value` attribute. The content of the `value` attribute is HTML- encoded and therefore not susceptible to XSS. However, the content of the `name` attribute is written to the HTML document without any encoding or sanitization. ## Proof of Concept ## An attacker can exploit this vulnerability by ending the HTML attribute and element and then inserting, for example, a `script` tag. ```text https://idp.example.com/as/authorization.oauth2?response_type=code&client_id=CLIENT&redirect_uri=https%3A%2F%2Fapp.example.com%2Fcb&%22%3E%3Cscript%3Ealert(1)%3C%2fscript%3E ``` The last parameter reads as follows when URL-decoded: ```html "><script>alert(1)</script> ``` This leads to the following HTML response (shortened for readability): ```html <form method="post" action="[...]"> <input type="hidden" name="REF" value="[...]"/> <!-- ... --> <input type="hidden" name=""><script>alert(1)</script>" value=""/> <!-- ... --> </form> ``` ## Recommended Countermeasures ## We recommend to HTML-encode the parameter name the same way the parameter value is encoded. ## Timeline ## * `2019-03-05` Identified the vulnerability in version < 1.5 * `2019-03-25` Contacted the vendor via support * `2019-05-24` Finding review with Ping Identity and SBA Research * `2019-07-11` Publication of CVE-2019-13564 ## References ## * [NIST NVD entry of CVE-2019-13564](https://nvd.nist.gov/vuln/detail/CVE-2019-13564) ## Credits ## * Thomas Konrad ([SBA Research](https://www.sba-research.org/))