OpenAI's Atlas and Perplexity's Comet browsers are vulnerable to attacks that spoof the built-in AI sidebar and can lead users into following malicious instructions. The AI Sidebar Spoofing attack was devised by researchers at browser security company SquareX and works on the latest versions of the two browsers. The researchers created three realistic attack scenarios where a threat actor could use AI Sidebar Spoofing to steal cryptocurrency, access a target's Gmail and Google Drive services, and hijack a device. Atlas and Comet are agentic AI browsers that integrate large language models (LLMs) into a sidebar for users to interact with while browsing: ask to summarize the current page, execute commands, or perform automated tasks. Comet was released in July, while ChatGPT Atlas became…