Revan the modifying of code in itself is not illegal, and the free supply of this code, if it is not for sale elsewhere, is also *in most countries* legal. In some countries copyright also gives the right to refuse any distribution. Assuming that these people do not originate from one of these countries, then supplying installation for a fee is perfectly legal. Of course you cold jsut as easily revoke permission to use the code from these sites, and file a DMCA notification to their hosts