How to defend against cybercrime
Category : Preparedness
Why multi-layered backup is key to business continuity in the battle against cybercrime
This article was originally published in Continuity Central.
- I have been advising people to use multiple backups for some time now but most of the time even just one backup seems to be a burden for people.
- This article Published: Tuesday, 14 November 2017 gives some insight into why it’s so important to have a multi-layered backup strategy to protect against ransomware and other threats.
When it comes to cyber attacks, Gareth Griffiths says that having a comprehensive business continuity plan is no use if the backups themselves are not secure. Using the example of UK NHS Trusts, Gareth explains why there needs to be more emphasis on the robustness of protection.
NHS England recently released its 2017/2018 Data Security and Protection Requirements, which sets out ten data security standards. This follows a UK National Audit Office (NAO) report criticising the NHS for its handling of the WannaCry attack earlier this year. While there is much to commend in this report I do not think this goes far enough.
One of those data security standards states that “a comprehensive business continuity plan must be in place to respond to data and cyber security incidents”. We think there should be more emphasis on the robustness of protection. Having a comprehensive plan is no use if the backups themselves are not secure.
When backup isn’t enough
Just as disaster recovery is an essential component of business continuity in the battle against cybercrime, in the case of ransomware attempts, backup is critical. But, increasingly, we’re seeing that having a single backup strategy is not sufficient and, depending on the storage media, potentially even part of the problem.
Historically, there was little risk to backups themselves, yet ransomware adds a new dimension that threatens and attacks not just the data, but also the backups, as was the case with the WannaCry attack.
Because the risks to NHS systems have evolved, the precautions to protect against new threats are evolving too. Similarly, as the drivers for backing up data changes, the way backups are performed should too.
When backup is part of the problem
Today, many NHS Trusts use online de-duplication devices as their primary backup media. These devices can store many generations of backup in a small footprint at a reasonable cost and they are convenient to use and quick to restore from, i.e. no fetching tapes from offsite storage. BUT, they may actually be more vulnerable to malicious or malware attack, as demonstrated by WannaCry’s proficiency at encrypting files. And, on their own, they present a single point of failure.
While you can protect the single failure point by replicating the device to another location, that does not protect against deliberate corruption. Resilience features like replication are great if one piece of hardware fails, but no defence against deliberate corruption; they simply ensure that the data is perfectly corrupted in multiple locations.
Typically, de-duplication devices look just like any other file server (they typically present an SMB share). Unfortunately, that is just the sort of thing that ransomware looks for. Network file servers are where most sites keep their data, so the ransomware looks for these and encrypts them.
In effect, you may have made your backups convenient and easy to use, but also easy to damage and vulnerable to malware like WannaCry. What better way for a cybercriminal to incentivise an organization to pay up than by corrupting their backups as well as the data?
Lessons from history
- Ten years ago we backed up to tape: safe but slow and inconvenient to restore;
- Five years ago we changed to backup to online deduplication: Quick, convenient but vulnerable.
- Today we need both.
Traditionally, data backups were written to tape and stored offsite. While there were, and still are, of course, physical threats to backups, such as damage to hardware and physical disasters (fires and flood, for example) they were not vulnerable to cyber attack.
An offsite tape in a fire-safe with the write-protect switch set remains the safest form of backup from any threats, cyber or otherwise. Backups are best protected when they are maintained offline from production environments to avoid ransomware viruses corrupting backup copies. We refer to this as the ‘gold standard’.
While having an offline or tape backup is a good secure media, it is more challenging to use. Tapes have to be located, loaded and positioned and can only be used by one process at a time. For this reason, many Trusts have a desire to move away from tape, but they haven’t always considered the potential vulnerability of disk-based backups.
Rather than moving away from tape completely, at BridgeHead, we believe that offline media must supplement online backups and provide the second layer of protection. So how can you get the best of both worlds – convenient quick access and secure offsite protection?
We recommend an easy to restore from, but less secure first stage backup with a ‘cascade’ on to tape or similar offline removable media. Because the cascade copying the data is all on backup servers it does not impact production systems. This is commonly called Disk to Disk to Tape (D2D2T). The final copy doesn’t have to be tape, but it must be safe against malware, secure and offsite. Tape is arguably still the simplest media, although some strongly authenticated cloud storage could be considered.
The disk copy, most likely de-duplication, is used for quick convenient restores, while tape is used for site disasters or if the de-dupe device itself gets damaged physically or corrupted. The first layer might be a backup to a de-duplication store or a storage array snapshot that is then cascaded onto tape, or similar offline media, for long-term and more robust backup.
Much like any other sector, NHS Trusts need to make sure they have robust data backup. There is no one single best practice for backup. But considering, planning and testing disaster recovery and business continuity strategies regularly is an essential part of keeping up with evolving threats and minimising impact on patient care through downtime.
Even with the best firewalls and protection in place, we need to accept that cyber attacks can and will still happen. It isn’t so much if you catch malware as when. What is crucial is that healthcare organizations recover quickly with as little impact on patients as possible.
As the data security standard recommends, Trusts should have a written continuity plan. A well-designed and, crucially, well-tested backup and disaster recovery plan is critical to surviving a cyber attack and we believe that multi-layered backup should be core to that plan.
Gareth Griffiths, Chief Technology Officer, BridgeHead Software. BridgeHead Software delivers data management solutions to healthcare organizations across the globe enabling them to improve patient care.