The current version of the ZeuS botnet uses classical copy protection mechanisms to prevent the use of unlicensed pirate copies. ZeuS is a malware toolkit used, for instance, to steal online banking data. The basic version currently costs about $3,000 to $4,000.
Security firm SecureWorks has discovered that the ZeuS server only works with a system specific key. Similar to the Windows OS, the malware creates a kind of fingerprint of the respective hardware configuration when first started. The vendor then provides the user with a personalised licence key for this configuration.
http://www.h-online.com/security/news/item/Botnet-with-integrated-copy-protection-956502.html