Introduction
At Doyensec, we decided to perform a vulnerability research activity on the SMB3 Kernel Server (ksmbd), a component of the Linux kernel. Initially, it was enabled as an experimental feature, but in the kernel version 6.6, the experimental flag was removed, and it remains stable.
Ksmbd splits tasks to optimize performance, handling critical file operations in kernel space and non-performance-related tasks, such as DCE/RPC and user account management, in user space via ksmbd.mountd. The server uses a multi-threaded architecture to efficiently process SMB requests in parallel, leveraging kernel worker threads for scalability and user-space integration for configuration and RPC handling.
Ksmbd is not enabled by default, but it is a great target for learning the SMB protocol while …
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