Anthropic said on Thursday that its artificial intelligence (AI) models "gained unauthorized access" to three outside organizations during testing that was supposed to be isolated from "real-world" systems.

The company reviewed 141,006 test sessions to find that three different versions of Claude, its AI model, improperly accessed the system of the three unnamed organizations.

"Claude compromised the impacted organizations' infrastructure using basic techniques, such as ‌exploiting ​weak passwords and unauthenticated endpoints," Anthropic said in a blog post.

The evaluation was launched after rival OpenAI disclosed last week that itsadvanced AI models went rogue during a security test and carried out a days-long hacking spree into a digital repository of AI technology known as Hugging Face.

However, unlike the incident with OpenAI's technology, Anthropic's AI models had access to the internet due to what the company described as a "misunderstanding" with its evaluation partner Irregular, which left the systems connected to the public internet.How did the Claude models go rogue?