While the SSH-2.0-Cisco-1.25 string is often associated with legacy code, the risk is not confined to the past. Cisco has disclosed several high-severity vulnerabilities in recent years that affect modern products and their SSH implementations.

: The simplest way to identify devices is to run an Nmap script ( -sV ) on port 22. Any response containing SSH-2.0-Cisco-1.25 should be documented for review.

Over globally were recently detected online with this specific banner. Main Vulnerabilities Terrapin Attack (Downgrade) and Pre-Auth RCE . Mitigation

The identifier is not a standard CVE (Common Vulnerabilities and Exposures) number, but rather a specific SSH banner string observed on some older Cisco devices.

The identification string SSH-2.0-Cisco-1.25 is a common sight for network engineers, appearing during SSH connections to a vast number of Cisco switches and routers. It is not merely a version number; it's a digital banner announced by the SSH server on a device as soon as a TCP connection is established on port 22.

nmap --script ssh2-enum-algos -p 22 <target> nmap --script ssh-hostkey --script-args ssh_hostkey=all -p 22 <target>

SSH0: Exchanging versions - SSH-2.0-Cisco-1.25 SSH0: send SSH message: outdated is NULL server version string: SSH-2.0-Cisco-1.25

Proactive detection and systematic mitigation are crucial for managing risk.

While this affects many devices showing the Cisco-1.25 banner, it specifically impacts those running the Erlang-based SSH service. Summary of Risk Exposure