Russia states many times, officially, that it supports Palestine's right for sovereignty, Putin & Abbas meet on a regular basis, Russia officially disapproved of Trump's Jerusalem shenanigans etc. Russian foreign minister, Lavrov, met with Hamas multiple times, officially, as well as meeting with Riyad al-Maliki just a little over a week ago in Moscow.
It's not in Israel's corner at all — but neither it is in Palestinian one. It uses it, like any other conflict that doesn't directly involve Russia, as a way to establish itself as a still relevant world power — and usually a one that's on the other side than USA is. In this case, with USA openly supporting Israel, Russia tries to perform the role of this great peace negotiator that would somehow magically solve the issue.