Spam purporting to be from my contacts

[321up]

We have both received a number of similar spam emails containing attachments and web links that purport to be from people in my contacts.  Most had been caught by the webmail spam filter.  Given that it's unlikely that some of the contacts know each other I assume that it's my contacts list the spammers have got somehow.  I've changed the password on my webmail, and checked email forwarding rules etc for tampering.  I've applied the latest updates to my computer and phone.  My computer is protected with internet security software and I have run a full scan.  I've not found anything conclusive to indicate a security breach.  Any suggestions please? 

[contango]

How many degrees of separation between your contacts? Presumably all of them know one person in common (you), so if any two have been compromised and your name was in both address books it wouldn't take a genius to link things together.

[Auntie Helen]

I was somehow hacked in February, apparently through my webmail account.

The spams purportedly from me are sent every few weeks now.

I changed my password but of course it's too late once the addresses have been harvested.

It's just something I have to live with.

[T42]

I read "my contacts" before seeing that it was the Ctrl-Alt-Del board & thought for an instant that the OP meant lenses.

Our professional site was hacked a few years back and hundreds of porn invitations went out in our name.  We received hundreds of emails from Disgusted of Dartford before it died down. Fortunately it was a shared hosting so the ISP was responsible, not us.