Ssh-2.0-cisco-1.25 Vulnerability High Quality
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.
The version "1.25" is archaic. It dates back to early Cisco IOS (Internetwork Operating System) implementations from the early-to-mid 2000s. While modern Cisco devices run much newer SSH implementations, seeing this specific version string in 2023/2024 is an immediate red flag. It suggests the device is running an operating system that has not been updated in potentially two decades.
Older Cisco SSH stacks often default to algorithms now considered "broken" or "weak":
The identifier is not a specific vulnerability itself, but rather the SSH banner string that many Cisco IOS and IOS XE devices use to identify their software version during an SSH handshake. When vulnerability scanners flag this string, they are typically reporting that the device is susceptible to a broader protocol-level flaw, most commonly the Terrapin Attack (CVE-2023-48795). What is the SSH-2.0-Cisco-1.25 "Vulnerability"? ssh-2.0-cisco-1.25 vulnerability
Legacy SSH implementations were designed in an era when cryptography standards were different. cisco-1.25 often supports:
This signature breaks down into three key functional components:
Look for:
: Successful exploitation yields full execution of arbitrary operating system commands. With a CVSS 3.1 score of 10.0 , an attacker completely bypasses local firewalls and access controls to gain total administrative command over the infrastructure target. 2. State-Machine Denial of Service (CVE-2020-3200)
On older codebases, flaws in how the SSHv2 engine processed RSA public key authentication requests allowed unauthenticated remote attackers to bypass the login phase entirely. By transmitting structurally malformed public keys or disrupting the state machine during the handshake, attackers could drop directly into the Virtual Teletype (VTY) command line interface with the privileges of the target user.
The core issue is a vulnerability in the SSHv2 implementation of Cisco IOS software. A crafted SSHv2 packet can cause the device to crash or reload. While "security by obscurity" isn't a primary defense,
Recently, security scanners and vulnerability assessments have increasingly flagged a specific SSH identification string: .
Ensure SSH version 2 is still enabled and banner changes to a newer string (e.g., SSH-2.0-Cisco-1.26 or higher).
: Refers to the internal version engine of Cisco’s native SSH implementation. It dates back to early Cisco IOS (Internetwork
