CVE-2025-14282: Dropbear SSH Authentication Bypass Flaw

CVE-2025-14282 Overview

A privilege escalation vulnerability has been identified in the Dropbear SSH server that affects the handling of socket forwarding operations in multi-user mode. When authenticating users, Dropbear performs socket forwardings requested by remote clients with root privileges before switching to the appropriate user context. This flaw allows any authenticated user to connect to any Unix domain socket with root credentials, effectively bypassing file system restrictions and peer credential verification mechanisms.

Critical Impact

Authenticated attackers can exploit this vulnerability to connect to privileged Unix domain sockets with root credentials, bypassing access controls including SO_PEERCRED and SO_PASSCRED checks typically used for authentication and authorization.

Affected Products

• Dropbear SSH Server (multi-user mode configurations)
• Systems utilizing Unix domain socket forwarding features
• Dropbear deployments with authenticated user access

Discovery Timeline

• 2025-12-16 - Vulnerability disclosed via Openwall OSS-Security Announcement
• 2026-02-12 - CVE CVE-2025-14282 published to NVD
• 2026-02-12 - Last updated in NVD database

Technical Details for CVE-2025-14282

Vulnerability Analysis

The vulnerability stems from an incorrect privilege assignment (CWE-266) in Dropbear's socket forwarding implementation. In multi-user mode, when a client requests socket forwarding, the Dropbear server processes these requests while still running with root privileges. The server only drops to the authenticated user's privilege level when spawning a shell or performing certain user-specific operations.

The recent addition of Unix domain socket support as a forwarding destination significantly amplifies the impact of this design flaw. Unix domain sockets commonly rely on peer credential checks (SO_PEERCRED and SO_PASSCRED) for authentication and authorization decisions. When Dropbear forwards connections to these sockets while still operating as root, the peer credential checks see root as the connecting user, not the actual authenticated SSH user.

This allows any user with valid SSH credentials to establish connections to sensitive Unix domain sockets that would normally be restricted to root or specific privileged users.

Root Cause

The root cause is an incorrect privilege assignment (CWE-266) in Dropbear's privilege handling during socket forwarding operations. The server maintains elevated privileges too long during the connection lifecycle, specifically when processing forwarding requests. The privilege drop to the authenticated user's context occurs only for shell spawning and certain file operations, leaving socket forwarding operations executing with root privileges.

Attack Vector

The attack requires network access and valid SSH credentials for the target Dropbear server. An authenticated attacker can request Unix domain socket forwarding through their SSH session. Because the forwarding operation executes with root privileges, the attacker can connect to any Unix domain socket on the system, regardless of file permissions or peer credential restrictions.

Common attack targets include:

• Docker daemon sockets (/var/run/docker.sock)
• System management sockets (systemd, D-Bus)
• Database Unix sockets with credential-based authentication
• Application-specific control sockets

The attacker's forwarded connection appears to originate from root, bypassing security checks that rely on peer credentials for authorization decisions.

Detection Methods for CVE-2025-14282

Indicators of Compromise

• Unexpected connections to privileged Unix domain sockets originating from sshd or Dropbear processes
• Audit logs showing root-privileged access to sensitive Unix sockets during active SSH sessions
• Unusual socket forwarding requests in SSH connection logs from standard user accounts
• Access to protected sockets (e.g., Docker daemon, systemd) by users without expected privileges

Detection Strategies

• Monitor SSH session logs for Unix domain socket forwarding requests (-L with Unix socket paths)
• Implement audit rules on sensitive Unix domain sockets to track connection attempts
• Review socket connections via ss -xp or lsof for unexpected root-owned connections during SSH sessions
• Deploy network detection signatures for anomalous SSH forwarding patterns

Monitoring Recommendations

• Enable verbose logging on Dropbear servers to capture forwarding requests
• Configure auditd rules for sensitive Unix socket access (e.g., Docker socket, D-Bus)
• Monitor for privilege escalation indicators following SSH authentication events
• Implement SentinelOne Singularity platform for real-time detection of privilege abuse patterns

How to Mitigate CVE-2025-14282

Immediate Actions Required

• Disable Unix domain socket forwarding if not required for operations
• Restrict SSH access to only necessary users and systems
• Review and audit existing Dropbear configurations for forwarding settings
• Apply vendor patches when available from Dropbear maintainers

Patch Information

A fix has been proposed via the GitHub Pull Request Update. Organizations should monitor the official Dropbear repository and mailing lists for patch releases. Additional technical discussion is available through the UCC Dropbear Mailing List Post and Openwall OSS-Security Update.

Workarounds

• Disable TCP and Unix socket forwarding by adding -j (disable local port forwarding) and -k (disable remote port forwarding) options to Dropbear startup configuration
• Implement additional access controls on sensitive Unix domain sockets using SELinux or AppArmor policies
• Use firewall rules or socket activation policies to restrict which processes can connect to critical sockets
• Consider deploying alternative SSH implementations with proper privilege separation until a patch is applied

# Disable port forwarding in Dropbear configuration
# Add these options to the Dropbear startup command or configuration file
dropbear -j -k -p 22

# Alternative: Restrict forwarding per-user via authorized_keys
# Add to ~/.ssh/authorized_keys before the key:
no-port-forwarding ssh-rsa AAAAB3...