Hello,
Spybot - Search & Destroy quarantines the malware it removes in these zip-files, so you can restore them if something goes wrong. They are password protected so that the user does not accidently unzip those malicious quarantined files. Another reason for the password protection is that some anti virus tools scan zip archives and might "detect" the already fixed problems as still present threats.
The password is: recovery
Best regards
Sandra
Team Spybot