Vulnerability | Ssh-2.0-cisco-1.25

: Restrict the volume of SSH traffic that the device's central route processor accepts. This directly minimizes the risk of state-exhaustion and DoS attacks.

Older firmware distributions broadcasting this exact banner have historically introduced security defects within the user validation process.

A flaw in the state machine of specific Cisco IOS implementations allows a remote, unauthenticated attacker to bypass standard AAA (Authentication, Authorization, and Accounting) controls.

This public link is valid for 7 days and shares a thread, including any personal information you added. This link or copies made by others cannot be deleted. If you share with third parties, their policies apply. Can’t copy the link right now. Try again later. SSH Terrapin Prefix Truncation Weakness - Cisco Community ssh-2.0-cisco-1.25 vulnerability

While "security by obscurity" isn't a primary defense, you can prevent casual scanning from identifying your exact version. On some platforms, you can customize or suppress parts of the SSH banner via the banner command, though the protocol-level version string (Cisco-1.25) is often hard-coded into the stack. Summary Table Vulnerability Mitigation Security Downgrade Disable ChaCha20-Poly1305 and CBC ciphers. RCE (CVE-2025-32433) Full System Takeover Immediate software update/patching. Weak KEX/Ciphers Data Decryption Update ip ssh settings to use SHA-2 and CTR.

What you’ve written looks like an (e.g., SSH-2.0-Cisco-1.25 ), which typically indicates:

As of late 2024 and early 2025, security reports indicated that hundreds of thousands of devices worldwide were still reporting the SSH-2.0-Cisco-1.25 banner. : Restrict the volume of SSH traffic that

The string ssh-2.0-cisco-1.25 is more than just a version number; it is a marker of technical debt. It represents a time capsule of security weaknesses that have long since been solved. In an era of automated ransomware and sophisticated state-sponsored attacks, leaving such a device exposed is an invitation for disaster. Network administrators must prioritize the identification and remediation of these legacy systems to maintain the integrity of their infrastructure.

: The communication relies on the modern, cryptographically secure SSH Version 2 protocol.

(use Telnet only on a secure OOB network). A flaw in the state machine of specific

Older Cisco SSH implementations, including those that may return the 1.25 identifier, have been subject to other notable security advisories: What is Cisco-1.25 in ssh logging.

1. Critical Erlang/OTP SSH Pre-Authentication RCE (CVE-2025-32433)