Need help with a hacked site

[Julius2020]

How to remove from the Google index pages of my site that were created by a virus  Japanese keyword hack?

It is necessary to remove from the Google index links to the pages of my site that were created by a virus - about 43 800 pages in Google index. The virus and the pages it created were removed from the site. A week ago, changes were made to the sitemap for reindexing. But so far the pages have not been deleted - moreover, new "garbage" pages appear in Google Webmaster. The site has no more than 100 "real" pages in the index. Everything else is non-existent links to garbage pages.
The main question we have now is how to remove this spam information from the Google index?

[edited by: not2easy at 2:38 am (utc) on Nov 19, 2020]
[edit reason] no links please [/edit]

[phranque]

welcome to WebmasterWorld [webmasterworld.com], Julius2020!

what response do you get when these "garbage" urls are requested?
it would be especially useful to know what the response is when you provide a googlebot user agent string.

have you used Google Search Console to gather information about these urls?

[not2easy]

Removing suspect files is the first step, but if new content is being created on your site, it has not been completely fixed. Google offers help to understand the ways that sites can be affected, along with tools to help you find and fix problems: [developers.google.com...]

One recent thread that can give you some insight and links to tools to deal with getting your site cleaned up and re-approved is here: [webmasterworld.com...]

An older thread offers ideas on how to determine exactly what is causing (and how to prevent) any hijacking (if that is involved) issues: [webmasterworld.com...]

Until you determine the cause or source of the problem you can't start to get rid of it.

[Julius2020]

phranque, the response now is: "This is a 404 (Not Found)". <snip> Yes, I used Google Search Console to gather information about these urls. I have a complete list of already deleted fake spam pages. How to remove them from Google now?

not2easy
There is currently no viral activity on the site. Including it is not fixed by the antivirus plugins that are now installed on the site.
The source of the problem was the "hole" SEO plugin - removed now.
The main question now is how to get rid of already non-existent pages in the Google index.

[edited by: not2easy at 4:25 am (utc) on Nov 19, 2020]
[edit reason] Please see ToS [webmasterworld.com] [/edit]

[not2easy]

If the URLs return a 404 response, Google will remove those URLs from its index.

[phranque]

the response now is: "This is a 404 (Not Found)".

The source of the problem was the "hole" SEO plugin - removed now.

so the response was not a 404 when google initially discovered and crawled those urls?

how to get rid of already non-existent pages in the Google index

you must wait until google recrawls those urls and reindexes the response.
have you checked to see if googlebot has crawled those urls and gotten a 404 response?
you might consider temporarily uploading an xml sitemap containing these "garbage" urls so you can track and perhaps initiate the recrawl and removal of these urls.