CVE-2018-15473

MEDIUM LAB

OpenSSH < 7.7 - User Enumeration via Authentication Request Timing

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 54 public exploits for CVE-2018-15473. PoCs published by Justin Gardner, Matthew Daley, Leap Security, including Metasploit module auxiliary/scanner/ssh/ssh_enumusers.

AI-analyzed exploit summary This exploit leverages a timing-based vulnerability in OpenSSH versions prior to 7.7 to enumerate valid usernames by malforming SSH packets during authentication. It uses Paramiko to manipulate packet handling and detect differences in server responses.

Description

OpenSSH through 7.7 is prone to a user enumeration vulnerability due to not delaying bailout for an invalid authenticating user until after the packet containing the request has been fully parsed, related to auth2-gss.c, auth2-hostbased.c, and auth2-pubkey.c.

Exploits (54)

exploitdb WORKING POC VERIFIED
by Justin Gardner · pythonremotelinux
https://www.exploit-db.com/exploits/45233

This exploit leverages a timing-based vulnerability in OpenSSH versions prior to 7.7 to enumerate valid usernames by malforming SSH packets during authentication. It uses Paramiko to manipulate packet handling and detect differences in server responses.

Classification
Working Poc 100%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH < 7.7
No auth needed
Prerequisites: Network access to the target SSH service · Paramiko library installed
devstral-2 · analyzed Feb 16, 2026 Full analysis →
exploitdb SCANNER VERIFIED
by Matthew Daley · pythonremotelinux
https://www.exploit-db.com/exploits/45210

This script exploits CVE-2018-15473, an authentication bypass vulnerability in OpenSSH, by manipulating the SSH message handling to determine valid usernames without proper authentication. It uses Paramiko to interact with the SSH server and checks for username validity based on the server's response.

Classification
Scanner 95%
Attack Type
Auth Bypass
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions affected by CVE-2018-15473
No auth needed
Prerequisites: Network access to the target SSH server · Paramiko library installed
MITRE ATT&CK
devstral-2 · analyzed Feb 16, 2026 Full analysis →
exploitdb WORKING POC
by Leap Security · pythonremotelinux
https://www.exploit-db.com/exploits/45939

This exploit leverages a malformed SSH packet to enumerate valid usernames on a target system by manipulating Paramiko's message handling. It exploits CVE-2018-15473, which allows user enumeration due to differences in error responses.

Classification
Working Poc 100%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions prior to 7.7
No auth needed
Prerequisites: Network access to the target SSH service · Paramiko library installed
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 533 stars
by Rhynorater · poc
https://github.com/Rhynorater/CVE-2018-15473-Exploit

This is a functional exploit for CVE-2018-15473, an OpenSSH username enumeration vulnerability. It uses malformed SSH packets to determine valid usernames by exploiting timing differences in authentication responses.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions < 7.7
No auth needed
Prerequisites: Network access to the target SSH service · Paramiko library installed
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 156 stars
by trimstray · poc
https://github.com/trimstray/massh-enum

This repository contains a Python script for enumerating valid usernames on OpenSSH servers (versions 2.3 to 7.4) by exploiting CVE-2018-15473. The script sends malformed packets to determine if a username exists based on the server's response behavior.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH 2.3 to 7.4
No auth needed
Prerequisites: Network access to the target SSH server · Python 2.7 with Paramiko library
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 111 stars
by epi052 · poc
https://github.com/epi052/cve-2018-15473

This PoC exploits CVE-2018-15473, a user enumeration vulnerability in OpenSSH through 7.7, by sending malformed SSH2_MSG_USERAUTH_REQUEST packets to determine valid usernames. It uses Paramiko for SSH communication and monkey-patching to manipulate packet handling.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH through 7.7
No auth needed
Prerequisites: Network access to the target SSH service · Paramiko library installed
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 43 stars
by Sait-Nuri · poc
https://github.com/Sait-Nuri/CVE-2018-15473

This PoC exploits CVE-2018-15473, an SSH username enumeration vulnerability in OpenSSH versions 2.3 to 7.7. It manipulates SSH packet handling to distinguish between valid and invalid usernames by malforming the MSG_SERVICE_ACCEPT packet.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH 2.3 to 7.7
No auth needed
Prerequisites: Network access to the target SSH service · Paramiko library installed
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 17 stars
by r3dxpl0it · poc
https://github.com/r3dxpl0it/CVE-2018-15473

This PoC exploits CVE-2018-15473, a username enumeration vulnerability in OpenSSH 7.7 and earlier. It sends malformed packets to determine if a username exists by observing the server's response behavior.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions 7.7 and earlier
No auth needed
Prerequisites: Network access to the target SSH service · List of usernames to enumerate
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 4 stars
by sergiovks · poc
https://github.com/sergiovks/SSH-User-Enum-Python3-CVE-2018-15473

This repository contains Python3 scripts for exploiting CVE-2018-15473, an OpenSSH user enumeration vulnerability. The scripts manipulate SSH protocol packets to determine valid usernames without authentication.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH < 7.7
No auth needed
Prerequisites: Network access to target SSH port · Paramiko library
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 3 stars
by MrDottt · poc
https://github.com/MrDottt/CVE-2018-15473

This PoC exploits CVE-2018-15473 (SSH user enumeration via timing attack) by measuring authentication response times to distinguish valid from invalid usernames. It uses Paramiko to interact with the SSH daemon and statistical analysis to determine user existence.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH (versions affected by CVE-2018-15473)
No auth needed
Prerequisites: network access to target SSH daemon · Python 2.7 with Paramiko and NumPy
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 3 stars
by gbonacini · poc
https://github.com/gbonacini/opensshenum

This repository contains a working PoC for CVE-2018-15473, an OpenSSH user enumeration vulnerability. The tool exploits a timing-based flaw to verify valid usernames on a target system and includes additional features like port scanning and fingerprinting.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions 2.3.0 to 7.7p1 (pre-July 2018 patch)
No auth needed
Prerequisites: OpenSSL 1.0.2h or later · C++11 compiler · automake/autoconf · libtool
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 2 stars
by JoeBlackSecurity · poc
https://github.com/JoeBlackSecurity/SSHUsernameBruter-SSHUB

This PoC exploits CVE-2018-15473, a username enumeration vulnerability in OpenSSH versions < 7.7. It uses malformed SSH packets to determine valid usernames and optionally attempts authentication with username/username credentials.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions < 7.7
No auth needed
Prerequisites: Network access to the target SSH server · Paramiko library installed
devstral-2 · analyzed Feb 16, 2026 Full analysis →
gitlab WORKING POC 1 stars
by epi052 · poc
https://gitlab.com/epi052/cve-2018-15473

This repository contains a functional Python script that exploits CVE-2018-15473, an OpenSSH user enumeration vulnerability. The script uses a monkey-patched Paramiko library to send malformed SSH2_MSG_USERAUTH_REQUEST packets, allowing detection of valid usernames based on the server's response.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH through 7.7
No auth needed
Prerequisites: network access to the target SSH service · Python 3.6+ with Paramiko library
devstral-2 · analyzed Feb 23, 2026 Full analysis →
nomisec SCANNER 1 stars
by anonymous121029034720384234234 · poc
https://github.com/anonymous121029034720384234234/py-network-scanner

This repository contains a network scanner toolkit with SSH exploitation capabilities, specifically targeting CVE-2018-15473 for username enumeration. It includes features for network reconnaissance, SSH security assessment, and advanced evasion techniques.

Classification
Scanner 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions vulnerable to CVE-2018-15473
No auth needed
Prerequisites: Network access to target SSH service · Python 3.6+ with required dependencies
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 1 stars
by OmarV4066 · poc
https://github.com/OmarV4066/SSHEnumKL

This PoC exploits CVE-2018-15473, an SSH user enumeration vulnerability in OpenSSH. It manipulates Paramiko's packet handling to malform boolean values, allowing detection of valid usernames via authentication responses.

Classification
Working Poc 90%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions vulnerable to CVE-2018-15473
No auth needed
Prerequisites: Network access to target SSH service · Paramiko library installed
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec STUB 1 stars
by mclbn · poc
https://github.com/mclbn/docker-cve-2018-15473

This repository provides a Docker setup to test pentest tools against CVE-2018-15473, a vulnerability in OpenSSH. It includes a docker-compose configuration but lacks actual exploit code or detailed instructions.

Classification
Stub 80%
Attack Type
Other
Complexity
Trivial
Reliability
Theoretical
Target: OpenSSH (version not specified)
No auth needed
Prerequisites: Docker · docker-compose
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 1 stars
by 0xrobiul · poc
https://github.com/0xrobiul/CVE-2018-15473

This exploit leverages CVE-2018-15473 to enumerate valid SSH usernames by manipulating the SSH authentication packet structure. It uses a modified Paramiko library to send malformed packets and distinguish between valid and invalid usernames based on the server's response.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH 2.3 to 7.7
No auth needed
Prerequisites: Network access to the target SSH service · Paramiko library installed
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec STUB 1 stars
by cved-sources · poc
https://github.com/cved-sources/cve-2018-15473

This repository contains a minimal setup for a vulnerable Docker container related to CVE-2018-15473, but lacks actual exploit code. The main.sh script only initializes and runs SSH in a loop, which is insufficient for demonstrating the vulnerability.

Classification
Stub 90%
Attack Type
Other
Complexity
Trivial
Reliability
Theoretical
Target: OpenSSH (version not specified)
No auth needed
Prerequisites: Docker environment · Access to the container
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 1 stars
by NHPT · poc
https://github.com/NHPT/SSH-account-enumeration-verification-script

This PoC exploits CVE-2018-15473, an SSH username enumeration vulnerability in OpenSSH. It manipulates the Paramiko library to malform packets and determine username validity based on server responses.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH (versions affected by CVE-2018-15473)
No auth needed
Prerequisites: Network access to target SSH service · Paramiko library installed
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 1 stars
by LINYIKAI · poc
https://github.com/LINYIKAI/CVE-2018-15473-exp

This repository contains a PoC for CVE-2018-15473, an OpenSSH username enumeration vulnerability affecting versions <7.7. The exploit leverages a timing-based side-channel to determine valid usernames by manipulating SSH authentication responses.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH <7.7
No auth needed
Prerequisites: Network access to target SSH service · Python 2.7 for poc.py and Python 3 for openssh.py
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by kaktus5454 · poc
https://github.com/kaktus5454/CVE-2018-15473

This repository contains a functional Python exploit for CVE-2018-15473, which allows enumeration of valid SSH usernames by analyzing server responses to malformed authentication packets. The tool supports single username checks and wordlist-based enumeration with multi-threading.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH 2.3 to 7.7
No auth needed
Prerequisites: network access to target SSH server · Python 3.6+ with paramiko library
devstral-2 · analyzed Apr 10, 2026 Full analysis →
nomisec SCANNER
by kikechans · poc
https://github.com/kikechans/-SSH-Enum-CVE-2018-15473

This repository contains a Python-based scanner for CVE-2018-15473, which exploits an information disclosure vulnerability in OpenSSH to enumerate valid usernames. The tool uses a timing-based approach and manipulates SSH authentication packets to distinguish between valid and invalid users.

Classification
Scanner 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions prior to 7.7
No auth needed
Prerequisites: paramiko library · network access to the target SSH server
devstral-2 · analyzed May 27, 2026 Full analysis →
nomisec WORKING POC
by kikechans · poc
https://github.com/kikechans/SSH-Enum-CVE-2018-15473

This repository contains a functional Python 3 exploit for CVE-2018-15473, an OpenSSH user enumeration vulnerability affecting versions prior to 7.7. The script uses Paramiko to send malformed SSH authentication requests and analyzes server responses to determine valid usernames.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH < 7.7
No auth needed
Prerequisites: network access to target SSH port · Python 3 with Paramiko library
devstral-2 · analyzed Apr 10, 2026 Full analysis →
nomisec WORKING POC
by wtbacon · poc
https://github.com/wtbacon/cve-2018-15473

This repository contains a functional exploit for CVE-2018-15473, which allows remote username enumeration in OpenSSH by sending malformed authentication requests. The exploit monkey-patches Paramiko to send a truncated SSH_MSG_USERAUTH_REQUEST packet and observes differential server responses to determine valid usernames.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH 2.3 through 7.7
No auth needed
Prerequisites: network access to target SSH server · Paramiko library
devstral-2 · analyzed Apr 10, 2026 Full analysis →
nomisec WORKING POC
by K3rn3l-32 · poc
https://github.com/K3rn3l-32/Threaded-CVE-2018-15473

This repository contains a functional Python 3 exploit for CVE-2018-15473, an OpenSSH user enumeration vulnerability. It uses multi-threading, wordlist support, and thread-safe patching of paramiko to send malformed authentication packets and detect valid usernames based on server responses.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH 2.3 through 7.7
No auth needed
Prerequisites: Python 3.8+ · paramiko · python-nmap · nmap (system binary)
devstral-2 · analyzed Apr 10, 2026 Full analysis →
nomisec WORKING POC
by Remnant-DB · poc
https://github.com/Remnant-DB/CVE-2018-15473

This repository provides a containerized lab environment to demonstrate CVE-2018-15473, an OpenSSH user enumeration vulnerability. It includes a Dockerfile to build a vulnerable OpenSSH 7.7p1 instance and scripts to run the lab locally.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH 7.7p1
No auth needed
Prerequisites: Docker or Podman · network access to the target port
devstral-2 · analyzed Mar 09, 2026 Full analysis →
gitlab WORKING POC
by gavz · poc
https://gitlab.com/gavz/CVE-2018-15473-Exploit

This repository contains a functional exploit for CVE-2018-15473, an OpenSSH username enumeration vulnerability. The exploit manipulates SSH packet handling to determine valid usernames by exploiting a timing difference in authentication responses.

Classification
Working Poc 100%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions < 7.7
No auth needed
Prerequisites: network access to the target SSH service · list of usernames to test
devstral-2 · analyzed Feb 23, 2026 Full analysis →
gitlab WORKING POC
by xer0dayz · poc
https://gitlab.com/xer0dayz/CVE-2018-15473-Exploit

This repository contains a functional exploit for CVE-2018-15473, an OpenSSH username enumeration vulnerability. The exploit uses malformed SSH packets to determine valid usernames on the target system by analyzing authentication responses.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions < 7.7
No auth needed
Prerequisites: network access to the target SSH service · OpenSSH version < 7.7
devstral-2 · analyzed Feb 23, 2026 Full analysis →
nomisec WORKING POC
by jubeenshah · poc
https://github.com/jubeenshah/CVE-2018-15473-Exploit

This repository contains a Python-based exploit for CVE-2018-15473, which targets OpenSSH versions < 7.7 to enumerate valid usernames via a timing attack. The exploit uses Paramiko to manipulate SSH packets and includes both original and simplified versions with modern compatibility fixes.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH < 7.7
No auth needed
Prerequisites: Network access to target SSH service · Python 3.7+ with Paramiko library
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec SCANNER
by Alph4Sec · poc
https://github.com/Alph4Sec/ssh_enum_py

This repository contains a Python script for SSH user enumeration via timing differences and authentication responses, exploiting CVE-2018-15473 in vulnerable OpenSSH versions (≤ 7.7). It uses Paramiko to measure response times and determine likely valid/invalid users.

Classification
Scanner 90%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH ≤ 7.7
No auth needed
Prerequisites: Network access to target SSH service · List of usernames to test
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by makmour · poc
https://github.com/makmour/open-ssh-user-enumeration

This is a functional PoC for CVE-2018-15473, an OpenSSH username enumeration vulnerability. It exploits a timing discrepancy in SSH authentication responses to determine valid usernames by sending malformed packets.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions < 7.7
No auth needed
Prerequisites: Network access to the target SSH server · A list of usernames to test
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by moften · poc
https://github.com/moften/cve-2018-15473-poc

This PoC exploits CVE-2018-15473, an OpenSSH user enumeration vulnerability, by attempting authentication with invalid passwords and analyzing server responses to determine valid usernames.

Classification
Working Poc 90%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: OpenSSH (versions prior to fix)
No auth needed
Prerequisites: Network access to target SSH server · Paramiko library
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by 0xNehru · poc
https://github.com/0xNehru/ssh_Enum_vaild

This repository contains a Python script and a Bash script that exploit CVE-2018-15473 to enumerate valid SSH usernames on OpenSSH servers by analyzing authentication responses. The scripts use a public key authentication bypass technique and parallel processing for efficiency.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions <= 7.7
No auth needed
Prerequisites: Linux/macOS with Bash · OpenSSH client · Paramiko library for Python script
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by SUDORM0X · poc
https://github.com/SUDORM0X/PoC-CVE-2018-15473

This PoC exploits CVE-2018-15473, a user enumeration vulnerability in OpenSSH through 7.7, by sending malformed authentication packets to determine valid usernames based on server responses. It supports single-user checks and wordlist-based enumeration.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: OpenSSH <= 7.7
No auth needed
Prerequisites: Network access to target SSH server · Python 3 with ssh2-python library
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by NestyF · poc
https://github.com/NestyF/SSH_Enum_CVE-2018-15473

This PoC exploits CVE-2018-15473, an OpenSSH username enumeration vulnerability, by manipulating Paramiko's message handling to distinguish valid from invalid users via timing and error responses. It supports single-user and wordlist-based enumeration with colored console output.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH 2.3 to 7.7
No auth needed
Prerequisites: Python 3.x · Paramiko library · Colorama library · Network access to target SSH service
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by MahdiOsman · poc
https://github.com/MahdiOsman/CVE-2018-15473-SNMPv1-2-Community-String-Vulnerability-Testing

This repository contains a Python-based exploit for CVE-2018-15473, which targets OpenSSH versions < 7.7 to enumerate valid usernames via a timing attack. It also includes tools for SNMP community string testing, though the primary focus is on the SSH username enumeration exploit.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH < 7.7
No auth needed
Prerequisites: Network access to the target SSH service · OpenSSH version < 7.7 running on the target
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by yZee00 · poc
https://github.com/yZee00/CVE-2018-15473

This PoC exploits CVE-2018-15473, an SSH user enumeration vulnerability in OpenSSH. It manipulates the paramiko library to malform packets and determine valid usernames by analyzing authentication responses.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions affected by CVE-2018-15473
No auth needed
Prerequisites: Network access to the target SSH service · Paramiko library installed
devstral-2 · analyzed Feb 16, 2026 Full analysis →
github WORKING POC
by cowsecurity · pythonpoc
https://github.com/cowsecurity/CVE-Exploits/tree/main/CVE-2018-15473

This repository contains a functional Python3 exploit for CVE-2018-15473, which allows SSH username enumeration by manipulating the SSH authentication process. The exploit leverages a timing and response discrepancy in OpenSSH versions 2.3 to 7.7 to distinguish valid from invalid usernames.

Classification
Working Poc 100%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH 2.3 to 7.7
No auth needed
Prerequisites: network access to the target SSH service · a list of usernames or a single username to test
devstral-2 · analyzed Feb 27, 2026 Full analysis →
nomisec SCANNER
by Moon1705 · poc
https://github.com/Moon1705/easy_security

This repository contains a collection of security tools, including subdomain enumeration (sublist3r), service scanning (masscan), and SSH brute-forcing. It does not contain a direct exploit for CVE-2018-15473 but includes tools that could be used in reconnaissance phases.

Classification
Scanner 90%
Attack Type
Other
Complexity
Moderate
Reliability
Reliable
Target: N/A
No auth needed
Prerequisites: Python environment · External tools like masscan and sublist3r
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec STUB
by 4xolotl · poc
https://github.com/4xolotl/CVE-2018-15473

The repository contains only a README.md file with a CVE identifier and no exploit code or technical details. It appears to be a placeholder or incomplete submission.

Classification
Stub 10%
Attack Type
Other
Complexity
Trivial
Reliability
Theoretical
Target: unknown
No auth needed
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by GaboLC98 · poc
https://github.com/GaboLC98/userenum-CVE-2018-15473

This PoC automates user enumeration for CVE-2018-15473 by leveraging a dictionary attack against an SSH service. It integrates with an external script (45939.py) to test each username for validity.

Classification
Working Poc 90%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: OpenSSH versions affected by CVE-2018-15473
No auth needed
Prerequisites: Access to the target SSH service · Dictionary file with potential usernames
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by Anonimo501 · poc
https://github.com/Anonimo501/ssh_enum_users_CVE-2018-15473

The repository contains two Python scripts that exploit CVE-2018-15473, an SSH user enumeration vulnerability. The first script checks if a target is vulnerable, while the second enumerates valid users by leveraging the flaw in OpenSSH's authentication mechanism.

Classification
Working Poc 90%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: OpenSSH versions affected by CVE-2018-15473
No auth needed
Prerequisites: Network access to the target SSH service · List of usernames for enumeration
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by philippedixon · poc
https://github.com/philippedixon/CVE-2018-15473

This PoC exploits CVE-2018-15473, a username enumeration vulnerability in OpenSSH versions < 7.7. It malforms SSH packets to determine valid usernames by analyzing authentication responses.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH < 7.7
No auth needed
Prerequisites: Network access to the target SSH server · Paramiko library installed
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by Wh1t3Fox · poc
https://github.com/Wh1t3Fox/cve-2018-15473

This PoC exploits CVE-2018-15473, an OpenSSH user enumeration vulnerability, by sending malformed SSH2_MSG_USERAUTH_REQUEST packets to determine valid usernames. It uses Paramiko with a monkey patch to trigger the flaw and supports multi-threaded wordlist attacks.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH through 7.7
No auth needed
Prerequisites: Network access to target SSH service · Python 3.6+ with Paramiko
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by 66quentin · poc
https://github.com/66quentin/shodan-CVE-2018-15473

This repository contains a Python-based exploit for CVE-2018-15473, an SSH user enumeration vulnerability. The exploit manipulates SSH packet handling to determine valid usernames without authentication. It includes a script to fetch SSH servers from Shodan and test them against a username wordlist.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions prior to 7.7
No auth needed
Prerequisites: Shodan API key · Python libraries: argparse, shodan, paramiko · username wordlist
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by pyperanger · poc
https://github.com/pyperanger/CVE-2018-15473_exploit

This Perl script exploits CVE-2018-15473, an OpenSSH user enumeration vulnerability, by sending a malformed SSH2_MSG_USERAUTH_REQUEST packet to determine valid usernames based on error responses. It hooks into Net::SSH::Perl to manipulate packet handling and detect integrity errors.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH < 7.7
No auth needed
Prerequisites: Perl with Net::SSH::Perl and Crypt::Curve25519 dependencies
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by WildfootW · poc
https://github.com/WildfootW/CVE-2018-15473_OpenSSH_7.7

This PoC exploits CVE-2018-15473, an OpenSSH user enumeration vulnerability, by sending malformed SSH2_MSG_USERAUTH_REQUEST packets to determine valid usernames. It uses Paramiko for SSH communication and monkey-patching to manipulate packet handling.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH through 7.7
No auth needed
Prerequisites: Network access to the target SSH service · Paramiko library installed
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by Dirty-Racoon · poc
https://github.com/Dirty-Racoon/CVE-2018-15473-py3

This PoC exploits CVE-2018-15473, an authentication bypass vulnerability in OpenSSH, by manipulating SSH message handling to enumerate valid usernames. It uses Paramiko to malform packets and trigger authentication errors for invalid users.

Classification
Working Poc 95%
Attack Type
Auth Bypass
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions affected by CVE-2018-15473
No auth needed
Prerequisites: Network access to target SSH service · Paramiko library
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by coollce · poc
https://github.com/coollce/CVE-2018-15473_burte

This PoC exploits CVE-2018-15473, an OpenSSH username enumeration vulnerability affecting versions <7.7. It malforms SSH packets to distinguish between valid and invalid usernames by manipulating Paramiko's packet handling.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH <7.7
No auth needed
Prerequisites: Network access to target SSH port · Paramiko library (version 2.4.1)
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by 1stPeak · poc
https://github.com/1stPeak/CVE-2018-15473

This PoC exploits CVE-2018-15473, a user enumeration vulnerability in OpenSSH <= 7.7. It leverages a timing-based attack by sending malformed SSH2_MSG_USERAUTH_REQUEST packets to determine valid usernames without authentication.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH <= 7.7
No auth needed
Prerequisites: Network access to the target SSH service · Paramiko library installed
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by CaioCGH · poc
https://github.com/CaioCGH/EP4-redes

This repository contains a functional PoC for CVE-2018-15473, an OpenSSH username enumeration vulnerability. It includes scripts to test and exploit the flaw by malforming SSH packets to determine valid usernames on the target system.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions < 7.7
No auth needed
Prerequisites: Docker · Docker Compose · Python with Paramiko library
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec SCANNER
by An0nYm0u5101 · poc
https://github.com/An0nYm0u5101/enumpossible

This repository contains a bash script that scans SSH servers for password-based authentication and checks for the SSH user enumeration vulnerability (CVE-2018-15473). It uses a modified version of an existing exploit to identify vulnerable systems.

Classification
Scanner 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions affected by CVE-2018-15473
No auth needed
Prerequisites: List of SSH servers in ip:port format
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC
by trickster1103 · poc
https://github.com/trickster1103/-

This PoC exploits CVE-2018-15473, an authentication bypass vulnerability in OpenSSH, by manipulating the SSH message handling to enumerate valid usernames without proper authentication.

Classification
Working Poc 100%
Attack Type
Auth Bypass
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH versions before 7.8
No auth needed
Prerequisites: Network access to the target SSH server
MITRE ATT&CK
devstral-2 · analyzed Feb 16, 2026 Full analysis →
metasploit WORKING POC
by kenkeiras, Dariusz Tytko, Michal Sajdak, Qualys, wvu · rubypoc
https://github.com/rapid7/metasploit-framework/blob/master/modules/auxiliary/scanner/ssh/ssh_enumusers.rb

This Metasploit module enumerates SSH users via malformed packet or timing attack techniques, targeting OpenSSH vulnerabilities (CVE-2003-0190, CVE-2006-5229, CVE-2016-6210, CVE-2018-15473). It exploits differences in response times or error messages to distinguish valid from invalid usernames.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: OpenSSH (various versions)
No auth needed
Prerequisites: SSH service exposed · Public key authentication enabled (for malformed packet technique)
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (18)

Core 18
Core References
Mailing List, Patch, Third Party Advisory
http://www.openwall.com/lists/oss-security/2018/08/15/5
Issue Tracking, Mailing List, Patch, Third Party Advisory
https://bugs.debian.org/906236
Third Party Advisory vendor-advisory
https://security.gentoo.org/glsa/201810-03
Broken Link, Patch, Third Party Advisory, VDB Entry vdb-entry
http://www.securitytracker.com/id/1041487
Exploit, Third Party Advisory, VDB Entry exploit
https://www.exploit-db.com/exploits/45233/
Exploit, Third Party Advisory, VDB Entry exploit
https://www.exploit-db.com/exploits/45210/
Third Party Advisory vendor-advisory
https://usn.ubuntu.com/3809-1/
Mailing List, Third Party Advisory mailing-list
https://lists.debian.org/debian-lts-announce/2018/08/msg00022.html
Broken Link, Third Party Advisory, VDB Entry vdb-entry
http://www.securityfocus.com/bid/105140
Third Party Advisory vendor-advisory
https://www.debian.org/security/2018/dsa-4280
Exploit, Third Party Advisory, VDB Entry exploit
https://www.exploit-db.com/exploits/45939/
Third Party Advisory vendor-advisory
https://access.redhat.com/errata/RHSA-2019:0711
Third Party Advisory vendor-advisory
https://access.redhat.com/errata/RHSA-2019:2143

Scores

CVSS v3 5.3
EPSS 0.9863
EPSS Percentile 99.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact partial

Lab Environment

COMMUNITY
Community Lab
docker pull dockerbase/openssh-server
docker pull vulhub/openssh:7.7
+46 more repos

Details

CWE
CWE-362
Status published
Products (28)
canonical/ubuntu_linux 14.04
canonical/ubuntu_linux 16.04
canonical/ubuntu_linux 18.04
debian/debian_linux 8.0
debian/debian_linux 9.0
netapp/aff_baseboard_management_controller
netapp/cloud_backup
netapp/clustered_data_ontap
netapp/cn1610_firmware
netapp/data_ontap
... and 18 more
Published Aug 17, 2018
Tracked Since Feb 18, 2026