ONTAP 9.14

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Autonomous Ransomware Protection overview

Beginning with ONTAP 9.10.1, the Autonomous Ransomware Protection (ARP) feature uses workload analysis in NAS (NFS and SMB) environments to proactively detect and warn about abnormal activity that might indicate a ransomware attack.

When an attack is suspected, ARP also creates new Snapshot copies, in addition to existing protection from scheduled Snapshot copies.

Licenses and enablement

ONTAP releases License

ONTAP 9.11.1 and later


ONTAP 9.10.1

MT_EK_MGMT (Multi-Tenant Key Management)

  • If you are upgrading to ONTAP 9.11.1 or later and ARP is already configured on your system, you do not need to purchase the new Anti-ransomware license. For new ARP configurations, the new license is required.

  • If you are reverting from ONTAP 9.11.1 or later to ONTAP 9.10.1, and you have enabled ARP with the Anti-ransomware license, you will see a warning message and might need to reconfigure ARP. Learn about reverting ARP.

You can configure ARP on a per-volume basis using either ONTAP System Manager or the ONTAP CLI.

ONTAP ransomware protection strategy

An effective ransomware detection strategy should include more than a single layer of protection.

An analogy would be the safety features of a vehicle. You don’t rely on a single feature, such as a seatbelt, to completely protect you in an accident. Air bags, anti-lock brakes, and forward-collision warning are all additional safety features that will lead to a much better outcome. Ransomware protection should be viewed in the same way.

While ONTAP includes features like FPolicy, Snapshot copies, and SnapLock to help protect from ransomware, the following information focuses on the ARP on-box feature with machine learning capabilities.

What ARP detects

ARP is designed to protect against denial-of-service attacks where the attacker withholds data until a ransom is paid. ARP offers anti-ransomware detection based on:

  • Identification of the incoming data as encrypted or plaintext.

  • Analytics, which detects

    • Entropy: an evaluation of the randomness of data in a file

    • File extension types: An extension that does not conform to the normal extension type

    • File IOPS: A surge in abnormal volume activity with data encryption (beginning in ONTAP 9.11.1)

ARP can detect the spread of most ransomware attacks after only a small number of files are encrypted, take action automatically to protect data, and alert you that a suspected attack is happening.

No ransomware detection or prevention system can completely guarantee safety from a ransomware attack. Although it’s possible an attack might go undetected, ARP acts as an important additional layer of defense if anti-virus software has failed to detect an intrusion.

Learning and active modes

ARP has two modes:

  1. Learning (or "dry run" mode)

  2. Active (or "enabled" mode)

When you enable ARP, it runs in learning mode. In learning mode, the ONTAP system develops an alert profile based on the aforementioned analytic areas: entropy, file extension types, and file IOPS. After running ARP in learning mode for enough time to assess workload characteristics, you can switch to active mode and start protecting your data. Once ARP has switched to active mode, ONTAP will create ARP snapshots to protect the data if a threat is detected.

It’s recommended you leave ARP in learning mode for a minimum of 30 days, though you can switch to active mode at any time. Switching too early might lead to too many false positives. Beginning with ONTAP 9.13.1, ARP automatically determines the optimal learning period interval and automates the switch, which may occur before 30 days.

In active mode, if a file extension is flagged as abnormal, you should evaluate the alert. You can act on the alert to protect your data or you can mark the alert as a false positive. When you mark a false positive, ONTAP will update the ARP alert profile so that the file extension is not subsequently flagged. The command security anti-ransomware volume workload-behavior show shows file extensions that have been detected in the volume. (If you run this command early in learning mode and it shows an accurate representation of file types, you should not use that data as a basis to move to active mode, as ONTAP is still collecting other metrics.)

Beginning in ONTAP 9.11.1, you can customize the detection parameters for ARP. For more information, see manage ARP attack detection parameters.

Threat assessment and ARP Snapshots

In active mode, ARP assesses threat probability based on incoming data measured against learned analytics. A measurement is assigned when ARP detects a threat:

  • Low: the earliest detection of an abnormality in the volume (for example, a new file extension is observed in the volume).

  • Moderate: multiple files with the same never-seen-before file extension are observed.

    • In ONTAP 9.10.1, the threshold for escalation to moderate is 100 or more files. Beginning with ONTAP 9.11.1, the file quantity is modifiable; its default value is 20.

In a low threat situation, ONTAP detects an abnormality and creates a Snapshot of the volume to create the best recovery point. The ARP Snapshot uses the anti-ransomware-backup tag and is identifiable by its name, for example Anti_ransomware_backup.2022-12-20_1248.

The threat escalates to moderate after ONTAP runs an analytics report determining if the abnormality matches a ransomware profile. Threats that remain at the low level are logged and visible in the Events section of ONTAP System Manager. When the attack probability is moderate, ONTAP generates an EMS notification prompting you to assess the threat. ONTAP does not send alerts about low threats, however you can modify alerts settings beginning in ONTAP 9.14.1. For more information, see Respond to abnormal activity.

You can view information about a threat, regardless of level, in ONTAP System Manager’s Events section or with the security anti-ransomware volume show command.

ARP Snapshots are retained for a minimum of two days. Beginning with ONTAP 9.11.1, you can modify the retention settings. For more information, see Modify options for Snapshot copies.

How to recover data in ONTAP after a ransomware attack

When an attack is suspected, the system takes a volume Snapshot copy at that point in time and locks that copy. If the attack is confirmed later, the volume can be restored to this Snapshot, minimizing data loss.

Locked Snapshot copies cannot be deleted by normal means. However, if you decide later to mark the attack as a false positive, the locked copy will be deleted.

With the knowledge of the affected files and the time of attack, it is possible to selectively recover the affected files from various Snapshot copies, rather than simply reverting the whole volume to one of the snapshots.

ARP thus builds on proven ONTAP data protection and disaster recovery technology to respond to ransomware attacks. See the following topics for more information on recovering data.

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