CWE-79: Improper Neutralization of Input During Web Page Generation
Unauthenticated stored XSS in server-log delivered via username field from login-form
CWE-352: Cross-Site Request Forgery
An attacker could exploit the unauthenticated stored XSS vulnerability by injecting malicious code into the login form's username field. When the server-log is viewed, the malicious code will be executed, potentially allowing the attacker to steal user data or execute further attacks.
By exploiting the CSRF vulnerability, an attacker could add a task to the server that runs commands with NT-System privileges. This could potentially allow the attacker to take complete control of the server, access sensitive data, or disrupt service.
Proof Of Consept
RCE via XSS and CSRF
The attacker places the staged XSS into the username field and sends the login request. This will place the XSS stager in the server log and trigger when a administrator opens the log.
The XSS stager downloads and runs the XSS payload. The payload will add a task that runs the powershell downloadcradle every time someone connects to the server. Even unauthenticated connections.
The powershell-script downloaded in this example is a reverse shell, connecting back to the attacker. As the task runs as NT System on the server, the attacker will have full controll on the server.