Having access to backup copies of critical data is the only way to guarantee avoidance of costly ransomware payments, insurance claims, and extended downtime to business operations. All too often this advice is heard only after experiencing an attack, and in hindsight these simple steps seem obvious.
During ransomware incidents technology staff are commonly not aware of techniques used by these criminals to take advantage of ineffective backup routines. In our experience conducting incident response recent ransomware events involve the targeting of backup processes. Reconfiguration of backup technologies, deletion of cloud storage environments, and destruction of backup data discovered in their attack are all used to prevent you from a simple recovery.
When you wake up to discover encrypted systems, there are literally no copies of your critical data left to be restored, your business operations are crippled, and the only path forward is negotiations with criminals. This is, as terrifying as it sounds.
As dire as the situation appears, simple steps should be used to avoid it altogether.
Include critical data
Apply the rule of 3
Three copies of any critical data, two different storage technologies, one copy off-site. Although not as relevant to ransomware attacks this rule reinforces the reliability of backup data by avoiding single points of failure related to physical losses like fires and floods and also failures in backup technologies. In most cases we recommend the off-site copy of the data be the immutable one.
Use immutable storage
The third best practice to leverage an immutable storage service for one of the copies of backup data. These write-once read-many (worm) backup solutions prevent existing backups from being deleted until a pre-determined recovery time is exceeded no matter what level of access is obtained. This option exists in almost every modern cloud-based storage provider including Amazon S3, Microsoft Azure Storage, Google Cloud Storage, and many others. Combining immutable storage with regular online/on-premise backups
Simulation of an attack will validate your procedures. Build and hold scenario-based exercises to simulate a ransomware attack, and test your ability to recover critical data within an acceptable period of time. These test scenarios should assume that the criminal has administrative access and the ability to access backup systems.