Updated Jul 14, 2026

Vulnerabilities

Confirm valid OpenSSH usernames before credential attacks

Username enumeration against OpenSSH via CVE-2018-15473.

Agent

overview

What cve-2018-15473 does

Reach for this node after you find an OpenSSH service on 7.7 or earlier and need a validated username list before spraying or brute forcing.

Pass a host plus -w for a wordlist or -u for one name. Set -p for non-default ports and --threads for parallel checks; -v prints valid and invalid results.

Trickest runs the enumerator as a managed Vulnerabilities node that writes confirmed accounts to a file and folder for hydra or medusa.

source github.com/epi052/cve-2018-15473

use cases

Where cve-2018-15473 fits

Enumerate valid SSH accounts

Test a username wordlist against an OpenSSH server and confirm which accounts exist from the server's differing responses to a malformed auth request.

Confirm a single account

Pass one username with -u to check whether a specific account is present, useful when you already have a name to verify.

Narrow a credential attack

Feed validated usernames into password spraying or brute forcing so the attack targets real accounts instead of guessing both user and password.

Reach IPv6 and non-standard ports

Enumerate IPv6 SSH services and services on a non-default port that IPv4-only or port-22-only tools cannot reach.

reference

cve-2018-15473 inputs and flags

6 inputs
NameTypeFlagDescription
hostnameSTRING·Target host or IP to enumerate (positional).
usernamesFILE-wWordlist of usernames to test.
single-usernameSTRING-uA single username to test.
portSTRING-pTarget SSH port (default 22).
threadsSTRING--threadsNumber of enumeration threads (default 4).
verboseBOOLEAN-vPrint both valid and invalid usernames (default false).

Showing key inputs. cve-2018-15473 exposes 6 inputs in total.

example

Run cve-2018-15473

cve-2018-15473 · command
# test a username wordlist against an OpenSSH service on a custom portpython3 ssh-username-enum.py -p 2222 --threads 8 -w users.txt 198.51.100.24
sample output
[*] Starting user enumeration on 198.51.100.24:22[*] Loaded 214 usernames from users.txt[+] admin is a valid user[+] deploy is a valid user[+] git is a valid user[-] backup is not a valid user[-] oracle is not a valid user[*] Enumeration complete: 3 valid, 211 invalid

guidance

Choosing cve-2018-15473

Use this when an SSH service runs a vulnerable OpenSSH version and you want validated usernames before a credential attack. Confirm the service first with a port scanner, then pass results to hydra or medusa.

hydra

Network login brute forcer. Consumes the validated usernames this tool produces.

medusa

Parallel credential brute forcer. Another consumer of enumerated SSH accounts.

netexec

Multi-protocol credential and enumeration tool. Broader than this single-CVE check.

faq

cve-2018-15473 questions

It sends a malformed public-key authentication request during the SSH handshake. OpenSSH hangs up for a valid account but returns a normal auth failure for a missing name. The tool reads that difference and never completes a login.

Run cve-2018-15473 yourself

An SSH host and a username wordlist feed the enumerator, which exploits CVE-2018-15473 to confirm real accounts and writes the valid usernames as output.

Facts on this page come from the live Trickest tool library.