The Secure Shell (SSH) protocol has survived as an internet-facing management protocol for almost 30 years. Over the decades it has transformed from a single patented codebase to a multitude of implementations available on nearly every operating system and network-connected device.
What we did #
runZero conducted a deep dive into the SSH ecosystem and identified vulnerabilities across a wide range of implementations. During the research process, we developed an open-source tool, called SSHamble, that can be used to identify vulnerable implementations and extend our research. We presented this work at the Black Hat USA 2024 and DEF CON 32.
Why this research matters #
SSH is the most commonly exposed remote administration protocol outside of HTTP and is critical to the security of most organizations. This work highlights unexpected exposures in common and lesser-known SSH implementations.
Examples of attacks include:
- Unauthenticated remote access due to unexpected state transitions
Remote command execution in post-session login implementations
Information leaks through unlimited high-speed authentication requests
SSHamble, our open-source research tool, can be used to reproduce these attacks and adapt this research to new techniques. The SSHamble interactive shell provides raw access to SSH requests in the post-session (but pre-execution) environment, enabling simple testing of environment control, signal processing, port forwarding, and much more.
Get access to SSHamble #
Interested in doing your own SSH research or building upon runZero's? You can get SSHamble and use it for your own security testing.
Level up your knowledge of SSH and SSHamble with this special episode of runZero Hour, our monthly deep dive series with the runZero Research Team.
