|Blog hacked. Should I unlink it?|
So, the blog of mysite.com, that is hosted in a sub-domain (blog.mysite.com), was hacked and a ton of illegal product pages were inserted in it.
I already cleaned the mess in the blog, but I'm afraid the fact of mysite.com having a link in the top menu pointing to blog.mysite.com could affect the first.
The blog hasn't been updated in a year and doesn't have much importance, my main concern is with the main site.
I have no idea, but I would look in WMT and see if Googlebot has crawled any of the fake product pages. If so, can you see any changes in rankings that occurred AFTER the product pages were hacked in? It IS possible for these things not to hurt you, especially if you fix them quickly.
If Googlebot HAS crawled the fake pages, but your rankings haven't changed, that may also indicate you're okay.
If you're just concerned about erring on the side of caution, it might not hurt to delete the link for a few months. OTOH, that might cause Google to notice and dig deeper, or at least that's how it seems to me. Sometimes it's better not to change anything (other than the cleanup you already did, obviously).
Sorry - it's just really hard to say what's the "right" answer, but that would be my approach.
I would look at your backlinks in Majestic, OSE, Bing WMT, Google WMT, AHREF, etc. I'd be willing to bet that if they were sophisticated enough to hack your site and throw up a bunch of product pages that they ALSO built a bunch of backlinks to those illegal product pages. So your work is likely not done.
I would also use WMT at all of the engines to remove all traces of those pages from their indices and make sure that those pages are returning 404 or 410 HTTP statuses. I would NOT redirect those illegal product pages.
I had a similar problem, 2 blogs under my main website were hacked and 20.000 illegal pages were created. Blogs were fixed within a week.
After 2 months, I'm still clening up 404 errors under GWT, converting them into 410 errors to let google now those pages are gone. The main problem is that I see dozens of hacked blogs still pointing to those pages...
As soon as you see drops in rankings/traffic for the main website, unlink it from the hacked blog or you'll probably deal with unnatural links notice / penalty!
Thank you diberry, ZydoSEO and teokolo for the replies.
@teokolo, did you suffer any noticeable drop in the main website after your blogs were hacked?
@rlopes, my situation is a bit tricky, because I received a notice of suspected hacking for the main site as well, even if it was unaffected. Then I decided to make a reconsideration request for the main website which led to a penalty for unnatural links...
Before filling the reconsideration request I didn't notice any significant drop in the main website.