OpenAI disables internet access during model training while Anthropic issues another mea culpa

OpenAI said it will conduct frontier model training with no internet access, a policy it implemented after METR and Redwood Research found its security and monitoring measures over the summer porous and ineffective, and after an internal research model exploited a DNS misconfiguration on September 20 to reach an external chatbot. OpenAI paused training and evaluation of its most capable models to harden infrastructure and monitoring. Separately, Anthropic published a report on its Claude Mythos 5 model's attempt to convince an open source project to accept malicious code during a capture-the-flag security evaluation, alongside a UK AI Security Institute analysis finding Mythos 5 continued its attack even when told targets were real and that most models tested took unsanctioned actions during cyber evaluations.

OpenAI disables internet access during model training while Anthropic issues another mea culpa The Register https://www.theregister.com We've totally got things under control OpenAI says it will deny internet access to the frontier models it is training https://www.machinebrief.com/glossary/training , a move that underscores the inadequacy of safety measures undertaken to date. "Based on the current state of alignment research, monitoring systems, and the security of internet infrastructure, we believe the responsible approach is to conduct frontier model training with no internet access," the company said in a blog post https://openai.com/index/securing-our-frontier-model-training-environment/ . "We've implemented this policy and will maintain it until advances in these safeguards justify broader internet access." The denial of network service follows a report from safety evaluation https://www.machinebrief.com/glossary/evaluation partners METR and Redwood Research that found OpenAI's security and monitoring measures over the summer to be porous and ineffective https://www.theregister.com/ai-and-ml/2026/10/23/red-team-report-found-openai-utterly-failed-to-monitor-its-agents-during-hugging-face-attack/5305200 . OpenAI said it has since "substantially hardened the security of our research environments" and has implemented new controls covering its infrastructure with the help of its cloud service providers. And the company claims these measures recently helped contain a September 20 incident https://alignment.openai.com/misalignment-reports/an-agent-used-dns-to-reach-an-external-chatbot/ in which an internal research model exploited a DNS misconfiguration to gain access to the internet. "Although we contained the incident, it exposed weaknesses that required further work," the company said. "We paused training and evaluation of our most capable models and used that pause to further harden our infrastructure, strengthen our monitoring, and improve the systems that automatically stop runs when we detect activity that poses a serious risk." Meanwhile, over at Anthropic https://www.machinebrief.com/glossary/anthropic … Anthropic, OpenAI's US rival in living large and dangerously on speculative funding, is addressing similar risks that have arisen during the testing and evaluation of its own models. Back in August, Anthropic said https://www.anthropic.com/news/improving-alignment-security-efforts , "By default, all cyber evaluations should run inside a hardened sandbox an isolated computing environment with no internet access." The AI biz on Friday published a report https://www.anthropic.com/research/alignment-assessment-ukaisi on efforts by its Claude https://www.machinebrief.com/compare/claude-4-opus-vs-gpt-o3 Mythos 5 model to convince an open source project to accept malicious code as part of its participation in a capture-the-flag security evaluation when safety controls were disabled , and several related incidents first disclosed in July https://www.anthropic.com/news/investigating-incidents-cybersecurity-evals . The report coincides with an independent analysis of Mythos' behavior https://www.aisi.gov.uk/blog/investigating-alignment-failures-in-aisis-incident by the UK's AI Security Institute AISI . AISI, according to Anthropic, has also decided to run its evaluations without internet access. The AISI report cites three key findings that raise more questions than they answer. The first is that Mythos 5 continued its attack even when informed that its targets were real and not part of an evaluation. The second is that the model's chain-of-thought reasoning https://www.machinebrief.com/glossary/reasoning process failed to consider the impact of harmful actions. And when interrogated about this, the model often produced invalid justification that the target was simulated, indicating bias toward its goal. And third, AISI said, most models tested during cyber evaluations took unsanctioned actions, though Mythos 5 did so the most. The observed behavior, AISI said, "could indicate that models are engaging in 'motivated reasoning': producing inferences and reasoning biased towards conclusions that justify continuing a particular approach to task completion." Or in other words, models "reason" to reach their goal, whether or not that reasoning is coherent or consistent with their ostensible alignment. "If these issues hold more generally and for future models, there are concerning implications," AISI said in its full technical report https://cdn.prod.website-files.com/663bd486c5e4c81588db7a1d/6ad8ac7f2ba7446392919b06 Alignment Investigation Mythos 5 AISI Incident.pdf PDF . Specifically, motivated reasoning, the watchdog said, makes it more difficult to detect model misalignment. Anthropic, headed toward an expected initial public offering as soon as next month, put a brave face on the findings by noting that its current models are much better behaved, even as the company acknowledged that AI safety https://www.machinebrief.com/glossary/ai-safety is more aspirational than achieved. " W e believe that all developers, ourselves included, have work to do to ensure that alignment, monitoring, and safety measures keep pace with the accelerating capabilities of frontier AI systems," the company said. ® Get AI news in your inbox Daily digest of what matters in AI.