Which Software bloated my hosts file?

I was just checking my hosts file and I saw over 4000 entries of pirate sites with 127.0.0.1

And after an empty line, there are the entries below:

0.0.0.0 pubads.g.doubleclick.net
0.0.0.0 securepubads.g.doubleclick.net
0.0.0.0 Error 404 (Not Found)!!1
0.0.0.0 gads.pubmatic.com
0.0.0.0 ads.pubmatic.com
0.0.0.0 tpc.googlesyndication.com
0.0.0.0 pagead2.googlesyndication.com
0.0.0.0 googleads.g.doubleclick.net

I am not interested in using any pirate sites, just I am wondering which software could have added all these lines.
I am only using Windows Defender, no other anti-virus or spyware installed.
Last saved day is March 3rd. I am writing that just in case it is something common.
Is there any known software that has access to windows hosts file and can change it? (Other than anti-virus and spyware software)

Windows 10 Pro 1909

Thanks.

Thanks for this.
It is surely helpful.
I did it.
I am still trying to figure out what kind of software can have access to hosts file.
I am guessing not a browser plugin or anything, as they would require admin access.
Thanks again.

Any software that has been granted elevated admin level access will have write permissions to the hosts file. Most installers require this level of access.

Setting the Read-Only attribute may not prevent writing to the file. This is only an advisory. Most text editors will honor this setting but other applications may not. Any software with write access to the file can do so without even resetting the Read-Only attribute

I would recommend a full scan with MalwareBytes.

Last saved date is March 3rd
Why not check in Control Panel and Programmes and Features whether any programmes or windows updates were installed at this date.