Can bad traffic by association ever be a good thing?

[MFCommunications]

Back in May, my client's website www.mfcomm.co.uk was hacked. Pages were added to the site which instantly received backlinks & traffic.  The secuirty flaw was plugged & offending pages deleted within the following weeks.  I also created 301 redirects for the most popular pages because the domain appeared to be affected by the increase in 404 errors.

Reviewing stats & Moz reports, I notice fresh backlinks - one from http://forum.kolodec.info/.  By association to the spurious page that was created as part of the security breach, should I distance the domain with any traffic from all referring sites?

Reviewing http://forum.kolodec.info/ in Open Site Explorer it only gets spam score = 4

So my question is, should I count all traffic by association as bad traffic & blacklist the domain or be more lenient?  More the point, what would Google think?

Regards, Terry

[Mobilio]

I think that you should check is this real visit or fake one. Check HTTP access logs about such referrer and see in Analytics (or other website analytics software that you used). Also visit URL where backlink should be. Then:

• In case of link to hacked pages - disavow ASAP. Bad guys make backlinks to hacked webpages to get higher position in SERP. But this could change your linking profile. And in some situation you may face Penguin algo filter.
• In case of link to other pages and source look shady - disavow ASAP. This could be even revenge for removed hack. Also can bring Penguin.
• In case of link to non-existing link i.e. bot traffic - leave. This is case when bot make "fake visit" tricking Analytics to count it. And webmasters go to inspect source. This is "curiosity driven visit", but messing your Analytics statistics.
• In case of regular link that is relevant - keep it. Example - i have link from Pakisanian forum about people discussing something like type X vs. type Y. And someone share link from mine site explaining "here is difference between them" in article that is exactly about their discussion.

So until you didn't see original source can be anything. Also please check question and answers here: 
https://moz.com/community/q/is-there-value-in-disavowing-links-if-you-there-is-no-google-penalty 
so disavowing isn't tool that you only use in case of penalty. You can use it even w/o penalty to make link profile clean as possible.