Uptick in healthcare organizations experiencing targeted DDoS attacks

Over the past few days, Cloudflare, as well as other sources, have observed healthcare organizations targeted by a pro-Russian hacktivist group claiming to be Killnet. There has been an increase in the amount of healthcare organizations coming to us to help get out from under these types of attacks. Multiple healthcare organizations behind Cloudflare have also been targeted by HTTP DDoS attacks and Cloudflare has helped them successfully mitigate these attacks. The United States Department of Health and Human Services issued an Analyst Note detailing the threat of Killnet-related cyberattacks to the healthcare industry.

A rise in political tensions and escalation of the conflict in Ukraine are all factors that play into the current cybersecurity threat landscape. Unlike traditional warfare, the Internet has enabled and empowered groups of individuals to carry out targeted attacks regardless of their location or involvement. Distributed-denial-of-Service (DDoS) attacks have the unfortunate advantage of not requiring an intrusion or a foothold to be launched and have, unfortunately, become more accessible than ever before.

The attacks observed by the Cloudflare global network do not show a clear indication that they are originating from a single botnet and the attack methods and sources seem to vary. This could indicate the involvement of multiple threat actors acting on behalf of Killnet, or it could indicate a more sophisticated, coordinated attack.

Cloudflare application services customers are protected against the attacks. Cloudflare systems have been automatically detecting and mitigating the attacks on behalf of our customers. Our team continues to monitor the situation closely and is prepared to deploy countermeasures, if needed.

As an extra precaution, customers in the Healthcare industry are advised to follow the mitigation recommendations in the “How to Prepare” section below.

Killnet is a group of pro-Russian individuals that gather and communicate on a Telegram channel. The channel provides a space for pro-Russian sympathizers to volunteer their expertise by participating in cyberattacks against Western interests. Previously, in the fourth quarter of 2022, Killnet called to attack US airport websites.

DDoS attacks, unlike ransomware, do not require an intrusion or foothold in the target network to be launched. Much like how physical addresses are publicly available via directories or for services like mail delivery, IP addresses and domain names are also publicly available. Unfortunately, this means that every domain name (layer 7) and every network that connects to the Internet (layers 3 & 4) must proactively prepare to defend against DDoS attacks. DDoS attacks are not new threats, but they have become larger, more sophisticated, and more frequent in recent years.

While Cloudflare’s systems have been automatically detecting and mitigating these DDoS attacks, we recommend additional precautionary measures to improve your security posture:

1. Ensure all other DDoS Managed Rules are set to default settings (High sensitivity level and mitigation actions) for optimal DDoS activation

2. Cloudflare Enterprise customers with Advanced DDoS should consider enabling Adaptive DDoS Protection, which mitigates traffic that deviates based on your traffic profiles

3. Deploy firewall rules and rate-limiting rules to enforce a combined positive and negative security model. Reduce the traffic allowed to your website based on your known usage.

4. Ensure your origin is not exposed to the public Internet (i.e. only enable access to Cloudflare IP addresses)

5. Customers with access to Managed IP Lists should consider leveraging those lists in firewall rules

6. Enable caching as much as possible to reduce the strain on your origin servers, and when using Workers, avoid overwhelming your origin server with more subrequests than necessary

7. Enable DDoS alerting to improve your response time

Though attacks are launched by humans, they are carried out by bots. Defenders who do not leverage automated defenses are at a disadvantage. Cloudflare has helped, and will continue to help, our customers in the healthcare industry prepare for and respond to these attacks.

Under attack? We can help. Visit this webpage or call us at +1 (888) 99 FLARE