• Ray clusters remain vulnerable to remote code execution via unauthenticated Jobs API
• Threat group “IronErn440” exploits flaw with AI-generated payloads, deploying XMRig cryptojacker
• Over 230,000 Ray servers are exposed online, up from a few thousand in 2023

Ray clusters, still vulnerable to a critical severity flaw discovered years ago, are being used for cryptocurrency mining, data exfiltration, and even Distributed Denial of Service (DDoS) attacks, experts have warned.

Cybersecurity researchers Oligo claim this is the second major campaign to leverage this same flaw.

Ray is an open source network that helps run Python programs faster by decentralizing and distributing the work across multiple machines. Its clusters are groups of computers – one head node and multiple worker nodes – that work together to run Ray tasks and workloads in a distributed and coordinated way.

Deploying and hiding XMRig

Back in 2023, it was discovered that Ray 2.6.3 and 2.8.0 carried a vulnerability that allowed a remote attacker to execute arbitrary code via the job submission API. However Anyscale, the company behind the product, did not fix it since it is designed to run in a “strictly-controlled network environment”.

In other words – it’s up to the users to secure their infrastructure and make sure the flaw does not get abused.

But abused, it was. First, between September 2023 and March 2024, and today. Oligo says that threat actors tracked as “IronErn440” are now using AI-generated payloads to infiltrate vulnerable clusters. By leveraging the bug, the attackers submit jobs to unauthenticated Jobs API, running multi-stage Bash and Python payloads hosted on GitHub and GitLab.

These payloads deploy malware to the devices – usually the infamous XMRig cryptojacker. While this cryptojacker is usually easily spotted (since it takes up 100% of the device’s processing power and renders it useless for pretty much anything else), the attackers tried to work around this issue by locking it to 60% of processing power.

Today, there are more than 230,000 Ray servers exposed to the internet, the researchers warned, saying that their numbers grew significantly compared to just “a few thousand” that were available when the vulnerability was first discovered.

Via BleepingComputer

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