Commvault only copies data that it manages. If malware inadvertently spreads into a storage area used by Commvault (such as shared folders), the malware is not blindly replicated to all other locations. Rather, data copies and instances are tracked and monitored. Commvault only replicates contents written to the first location to the second location.
Other third-party storage replication methods lack indexing and intelligence, so all content is moved. For example, if a deduplication storage NAS device presents shared folders, and malware is deposited in some files on the folder when a collection of files is written to the folders, the NAS device replicates all the contents. This "blind" replication produces new instances of the malware on the destination; this is a downside of hardware driven replication.
Alternatively, Commvault only replicates the files written to the first location to the second location. Commvault does not replicate other foreign files in the same share.