While I'm not going to single out the service if you check out the link above to the source code you may be able to figure it out. ;)
you might not, but i will. Its steemvoter. And anyone who has given their keys to steemvoter would be wise, IMO, to change them immediately.
... Yep. It is.
I stopped using their service after it became obvious they are saving posting keys (likely in plain text) and have the ability to misuse these posting keys.