Historically, Cisco devices running older versions of SSHv2 (which the scanner might be mislabeling or shorthand-naming) were vulnerable to a crafted packet that could cause a device reload.
Disable weak algorithms and ensure your RSA keys are at least 2048 bits .
Enterprise scanners frequently flag SSH 2.0 deployments because they accept legacy cryptographic properties. If a Cisco router or switch is configured to allow diffie-hellman-group1-sha1 or 3des-cbc , a passive network eavesdropper could potentially decrypt administrative traffic or harvest credentials. 3. Default or Hardcoded Credentials ssh20cisco125 vulnerability
If your vulnerability management portal raises a flag on an active system, implement the following hardening steps directly on your Cisco devices. Step 1: Restrict SSH to Strong Cryptographic Standards
ip ssh version 2 ip ssh time-out 60 ip ssh authentication-retries 3 ip ssh server algorithm encryption aes256-ctr aes192-ctr ip ssh server algorithm mac hmac-sha2-256 ip ssh server algorithm hostkey rsa-sha2-512 no ip ssh server algorithm hostkey rsa-sha1 ! Disable weak Historically, Cisco devices running older versions of SSHv2
The "ssh20cisco125" reference typically points toward a significant vulnerability affecting various Cisco products. This flaw originates from the Erlang/OTP SSH server and allows an attacker to execute arbitrary code remotely without needing valid credentials. Critical Vulnerability Details
The Secure Shell (SSH) protocol provides encrypted, secure remote access to network devices, replacing older, less secure protocols like Telnet. Cisco introduced SSH version 2 support across several IOS release trains, including 12.0S, 12.1T, 12.2, 12.2T, and 12.3T. However, the early integration of SSHv2, particularly when paired with TACACS+ (Terminal Access Controller Access Control System Plus) authentication, introduced critical flaws. If a Cisco router or switch is configured
This vulnerability was found in the Erlang/OTP SSH server, a component used across numerous network devices and software platforms. On April 16, 2025, it was disclosed that the server could be exploited before the authentication stage.
For the latest, definitive information, always refer to the official Cisco Advisory.
This term appears to be a misnomer, potentially combining "SSH," a year/version reference, and "Cisco."