Ssh-2.0-cisco-1.25 Vulnerability

That morning she made a quick plan. First, she isolated the affected device by moving management access to an alternate path and restricting SSH access in the firewall to only her workstation’s IP. She then pulled the exact firmware and configuration versions from the router and compared them against the vendor’s advisory. The advisory described a flaw in certain Cisco SSH implementations where malformed negotiation packets could cause a buffer overflow, allowing unauthenticated attackers to crash the SSH service or execute code.

If you cannot upgrade immediately, harden the existing SSH configuration to minimize attack surfaces. Run the following commands in global configuration mode: Router(config)# ip ssh version 2 Use code with caution. Set Strict Timeouts and Authentication Limits:

Restrict the SSH server to use only strong ciphers and Key Exchange (KEX) algorithms. Note: This requires a relatively modern IOS version. If the hardware is too old, this command may not be supported.

If you see SSH-2.0-Cisco-1.25 , the device be vulnerable, but you must verify the IOS version. ssh-2.0-cisco-1.25 vulnerability

On Cisco ASA devices that reported similar version strings (often overlapping with 1.25 ), there was a vulnerability where processing specific SSH packets would not free memory correctly. Over days or weeks, the device would exhaust memory and stop passing traffic. This required a reboot to resolve.

: Under specific, highly structured traffic patterns, the software's internal SSH state machine fails to resolve out-of-sequence errors correctly.

: If an environment has RSA public-key authentication configured , an attacker who discovers a valid local username can gain shell access with the underlying privileges assigned to that terminal line. 2. Device Reload and Denial of Service (CVE-2020-3200) That morning she made a quick plan

Devices reporting ssh-2.0-cisco-1.25 often default to outdated Key Exchange (Kex) algorithms, such as diffie-hellman-group1-sha1 . This algorithm uses a 768-bit prime modulus, which is computationally feasible to break with sufficient resources (e.g., a nation-state or well-funded attacker). Modern standards require 2048-bit (group14) or higher.

Proactive detection and systematic mitigation are crucial for managing risk.

Beyond direct security vulnerabilities, the SSH-2.0-Cisco-1.25 server is notorious for several implementation quirks that primarily cause operational headaches and, in some cases, could degrade the security posture of an SSH session. The advisory described a flaw in certain Cisco

(if SSHv1 is acceptable for your environment):

(use Telnet only on a secure OOB network).

When a network banner scan exposes an active SSH-2.0-Cisco-1.25 instance, it typically indicates exposure to several high-severity security vulnerabilities depending on the underlying operating system and software version. 1. The Erlang/OTP SSH Remote Code Execution (RCE) Flaw