SSH Host Keys < 2048 Bits Considered Weak

low Nessus Plugin ID 153954


The SSH server running on the remote host has public key that is considered weak.


Brute force setting must be enabled to use this plugin.

The remote SSH server has a host key size that is smaller than 2048 bits. NIST Special Publication 800-57 Part 3 Recommendation for Key Management recommends RSA keys greater or equal to 2048 bits in length.


Generate a new, larger SSH host key.

See Also

Plugin Details

Severity: Low

ID: 153954

File Name: ssh_key_size_weak.nasl

Version: 1.3

Type: remote

Family: General

Published: 10/13/2021

Updated: 8/16/2023

Supported Sensors: Nessus

Risk Information

CVSS Score Rationale: Tenable score for weak host key


Risk Factor: Low

Base Score: 2.6

Vector: CVSS2#AV:N/AC:H/Au:N/C:P/I:N/A:N

CVSS Score Source: manual


Risk Factor: Low

Base Score: 3.7

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Vulnerability Information

Excluded KB Items: global_settings/supplied_logins_only