What is Castlebot?

Castlebot is an unverified and potentially malicious automated agent that has appeared in some server logs with a user agent containing “castlebot.” There is no public documentation from reputable crawler operators (such as search engines, analytics companies, or media intelligence platforms) indicating that Castlebot is an official crawler with a legitimate indexing purpose. At the same time, cybersecurity researchers have identified a malware framework publicly referred to as “CastleBot” — an emerging Malware-as-a-Service (MaaS) platform — used by threat actors to deploy a range of malicious payloads, including backdoors and ransomware-related components.

Security analysts note that the malware CastleBot framework is designed with multiple stages and sophisticated techniques to evade detection and deliver additional threats, such as infostealers, remote access trojans, and ransomware loaders, often distributed via trojanized installers or deceptive downloads. Because of this name overlap and the lack of credible information confirming a benign operator, webmasters encountering traffic from a user agent labeled “Castlebot” should treat it with caution. Its behavior — especially if it repeatedly accesses comment or thank-you pages — more closely resembles spam or automated scanning traffic than a recognized content crawler.

Total recordings for castlebot: 32