CVE-2024-2873
📋 TL;DR
This vulnerability in wolfSSH allows malicious clients to create SSH channels without authenticating first, leading to unauthorized access to SSH server functionality. It affects all systems running vulnerable versions of wolfSSH server implementations. The high CVSS score reflects the authentication bypass nature of this flaw.
💻 Affected Systems
- wolfSSH
📦 What is this software?
Wolfssh by Wolfssh
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of SSH server allowing unauthorized command execution, file access, and potential lateral movement within the network.
Likely Case
Unauthorized access to SSH server capabilities including shell access, file transfers, and port forwarding without valid credentials.
If Mitigated
Limited impact if network segmentation restricts SSH access and proper authentication controls are enforced elsewhere.
🎯 Exploit Status
The vulnerability allows unauthenticated channel creation, making exploitation straightforward for attackers with network access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.4.17
Vendor Advisory: https://www.wolfssl.com/docs/security-vulnerabilities/
Restart Required: Yes
Instructions:
1. Download wolfSSH version 1.4.17 or later from official sources
2. Replace existing wolfSSH installation with patched version
3. Restart all services using wolfSSH
4. Verify the new version is active
🔧 Temporary Workarounds
Network Access Control
linuxRestrict SSH access to trusted networks only using firewall rules
iptables -A INPUT -p tcp --dport 22 -s trusted_network -j ACCEPT
iptables -A INPUT -p tcp --dport 22 -j DROP
SSH Port Change
linuxChange default SSH port to reduce automated scanning
Edit /etc/ssh/sshd_config: Port 2222
systemctl restart sshd
🧯 If You Can't Patch
- Implement strict network segmentation to isolate vulnerable SSH servers
- Deploy intrusion detection systems to monitor for unauthorized SSH access attempts
🔍 How to Verify
Check if Vulnerable:
Check wolfSSH version: if version is less than 1.4.17, the system is vulnerableCheck Version:
wolfssh-config --version or check library version in applicationVerify Fix Applied:
Confirm wolfSSH version is 1.4.17 or higher and test SSH authentication functionality📡 Detection & Monitoring
Log Indicators:
- SSH connections without authentication logs
- Multiple failed authentication attempts followed by successful channel creation
- Unusual SSH session patterns
Network Indicators:
- SSH traffic from unexpected sources
- SSH connections without proper authentication handshake
- Abnormal SSH channel creation patterns
SIEM Query:
source="ssh.log" AND (event="channel opened" NOT event="authentication successful")