Good anti-virus software should be able to delete infected emails at source - your ISPs mail server but you should be able to run it remotely. I have not been into recent version of anti-virus software so I'd advise you to check these in more detail. I'd start with Symantec.
As for legal action - well, that will most certainly cost more than anti-virus software and I don't think legal action will be able to recover any damages - if it was possible to get money out of people who fail to secure their home PCs and/or buy anti-virus software then we'd witness millions of lawsuits after each major virus outbreak. There can be lots of sources of emails - different people who opened email with virus and run it.
Tracking/Stopping the source of a virus, edward.terry, 3 Sep 14:24 One of our clients is suffering at the hands of Sobig.F. It appears that somebody has managed to get hold of one of their internal email addresses and is emailing the Sobig.F virus ...
Tracking/Stopping the source of a virus, Alex Chudnovsky, 4 Sep 16:00 Your client might want to consider using server-side anti-virus protection either by getting appropriate software or by using people like MessageLabs. SoBig is not the last email v ...
Tracking/Stopping the source of a virus, edward.terry, 4 Sep 19:36 Thanks Alex, useful information. Unfortunately, our client doesn't run or manage their own email server and their ISP doesn't provide this service. I guess that would only leave th ...
Tracking/Stopping the source of a virus, Alex Chudnovsky, 5 Sep 09:32 Good anti-virus software should be able to delete infected emails at source - your ISPs mail server but you should be able to run it remotely. I have not been into recent version o ...
Tracking/Stopping the source of a virus, Ashley Winton , 22 Sep 15:15 The law has some pretty flexible tools which include:
1) the law of torts allowing your client to take action for types of nuisance and for trespass;
2) trying to get the police ...
Tracking/Stopping the source of a virus, edward.terry, 24 Sep 10:48 Thanks Ashley, that's a really useful insight into other avenues of recourse.
The fact that the emails come in regularly (from 30-40 minutes periodicity) and they all have the s ...