Sites redirect to the left Instantfwding resource, has anyone met with this?

Question

Malware

Hello. Need help
Problem: We have a number of domains that redirect once a day to third-party resources that are blacklisted by Google because of this, the advertising company is blocked and it is not possible to access the site.
All support services unanimously repeat that we have not had any changes and the addresses have changed.
The local cache of providers Megafon and FirstVDS at the time of the error shows the HC record above.com, instead of ours.
Screenshot of the error:
Blocking RK from Google occurs due to the fact that the system finds blocked content on sites, the following is a list of links containing malware:

Answer 1

1. Your site has been hacked.
Check which files have been changed. If you use mercurial - hg status, if git - git status, if no VCS - suffer.
2. HTML/JS injection on your site (this is not a hack). The search engine receives a redirect using a specially made link with parameters.
See report in Webmaster search engine.
3. There is a JS injection in your banner scroller (or any other third party JS code).
Disable them temporarily.
4. Your panel at the domain registrar has been hacked. And the left NS-server is added.
Check the list of NS servers for your domain.

Answer 2

Exactly the same topic. We've been looking all day for the cause and can't find it