In one embodiment, a method for ransomware-aware file backup is implemented on a computing device and includes: backing up a target population of files from a target file location in a backup transaction, computing a backup delta score for the backup transaction, where the computing comprises comparing backup data from the backup transaction with backup data from a previous backup transaction, determining whether the computer backup delta score exceeds a pre-defined threshold, and upon the computed backup delta score exceeding the pre-defined threshold: determining that the backup transaction is indicative of a ransomware infection, and performing at least one counter-measure in response to the ransomware infection.