The exploit targets the . Security researchers identified that during the negotiation phase, specific input values (the "125" indicator in the name often refers to a particular byte sequence or length) are not properly validated.
If "ssh20cisco125" is a shorthand for a specific bug, you can search for official Common Vulnerabilities and Exposures (CVE) records on the NIST National Vulnerability Database . Common SSH-related CVEs for Cisco include: CVE-2020-3418: Resource exhaustion in Cisco IOS SSH. CVE-2018-0125:
A previously undocumented cryptographic implementation vulnerability, codenamed (CVSS 9.8 - Critical), is currently being exploited in the wild. Unlike standard SSH bugs, this flaw allows for pre-authentication command injection specifically when a Cisco device is configured to accept SSHv2 connections with legacy modular exponentiation parameters.
This vulnerability is prevalent in older or specialized Cisco software trains, including: Cisco iNode Manager Small Business VPN Routers (RV160, RV260, RV340 series). Cisco IOS / IOS XE Software (specific legacy versions). 5. Mitigation & Remediation CVE-2020-3200 Detail - NVD ssh20cisco125 vulnerability exclusive
The SSH-20 vulnerability arises from a weakness in the way Cisco IOS and IOS XE software handle SSH connections. When an attacker sends a specially crafted SSH packet to a vulnerable device, it can cause the device to crash or reload, resulting in a denial of service. This vulnerability is particularly concerning because it can be exploited remotely, without the need for authentication or any prior knowledge of the target device.
Want the raw PCAP of the attack? Reply "SSH125_PCAP" for an exclusive download link (Expires in 48 hours).
A systematic attack could reload core infrastructure components, causing widespread network downtime. The exploit targets the
| Vulnerable Versions | Fixed Version | |---|---| | 9.17.1 – 9.18.4.70 | 9.18.4.71 or later | | 9.19.1 – 9.20.4.9 | 9.20.4.10 or later | | 9.22.1.1 – 9.22.2.13 | 9.22.2.14 or later | | 9.23.1 – 9.23.1.18 | 9.23.1.19 or later |
In rarer, more complex scenarios, the memory corruption can lead to the exposure of small fragments of system memory, which might contain sensitive configuration data.
Cause the device to reload or crash if the exploit fails to gain full code execution. Bypass Authentication: This vulnerability is prevalent in older or specialized
Enterprise network hardware must balance interoperability with strict security. The following table highlights the differences between secure implementations and vulnerable conditions associated with legacy configuration strings: Vector Element Vulnerable / Legacy State Hardened Target State Risk Impact Concurrent SSHv1 & SSHv2 enabled SSHv2 Only enforced High; protocol downgrade interception Key Exchange (KEX) diffie-hellman-group1-sha1 ecdh-sha2-nistp256 , dh-group14-sha256 Medium; cryptographic break over time Authentication Triggers Unlimited login attempts per session Max limits enforced ( ip ssh authentication-retries ) High; brute-force credential stuffing Access Control Open listening on all logical VTY lines Restricted via Explicit Management ACLs Critical; wide-area network scanning Enterprise Hardening Playbook
If left unaddressed, the SSH20CISCO125 vulnerability poses several risks: