Thanks, this helps a lot.
I'm using blackmore v2.13.2.6 on ubunto 18.04 LTS for some weeks before the attack. Last days I migrated from the old wallet to a new one to get rid of the dust, but the attack persists as described. The attack leads to a heavy processor load until the wallet process disrupts or forks. So it's not only the legacy client, but the more client too.
A fast way of doing this is to dump your keys from Legacy and import them into More.
Dumping and restoring private keys makes no sense, because the dust is persisting.