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How the CVE Works
The PostgreSQL JDBC driver (pgjdbc) fails to enforce channel binding when configured with channelBinding=require. Despite this setting, the driver allows fallback to insecure authentication methods like password, MD5, GSS, or SSPI, which lack channel binding support. This flaw enables man-in-the-middle (MITM) attackers to intercept and manipulate connections believed to be secure. The vulnerability arises from improper validation during the authentication handshake, permitting weak methods even when strong channel binding was explicitly requested.
DailyCVE Form:
Platform: PostgreSQL JDBC
Version: 42.7.4 – 42.7.6
Vulnerability: Auth bypass
Severity: Critical
Date: Jun 11, 2025
Prediction: Patch by Jun 25, 2025
What Undercode Say:
Exploitation:
- Intercept TLS Handshake: Attacker positions between client and server.
- Downgrade Auth: Forces weaker auth (e.g., MD5) despite
channelBinding=require.
3. Steal Creds: Captures credentials via MITM.
Example MITM using sslstrip sslstrip -l 8080 -w /tmp/log iptables -t nat -A PREROUTING -p tcp --dport 5432 -j REDIRECT --to-port 8080
Protection:
1. Upgrade: Apply patch (v42.7.7+).
2. Enforce SSL: Set `sslMode=verify-full` in `jdbc:postgresql://…?sslMode=verify-full`.
- Disable Weak Auth: Modify `pg_hba.conf` to reject
md5,password.// Secure JDBC URL example String url = "jdbc:postgresql://host/db?sslMode=verify-full&channelBinding=require";
Detection:
-- Check active connections for weak auth SELECT usename, auth_method FROM pg_stat_ssl WHERE auth_method != 'scram-sha-256';
Log Analysis:
Monitor for auth fallbacks grep "authentication method used" /var/log/postgresql.log | grep -v "scram-sha-256"
Patch Verification:
Confirm JDBC version java -cp postgresql-42.7.7.jar org.postgresql.util.PGJDBCMain --version
Network Hardening:
Block non-SSL traffic iptables -A INPUT -p tcp --dport 5432 ! --tls-version 1.2 -j DROP
Code Fix (Driver-Level):
// Patch snippet enforcing channel binding
if (channelBindingRequired && !authMethod.supportsChannelBinding()) {
throw new PSQLException("Channel binding required but auth method unsupported");
}
References:
Sources:
Reported By: github.com
Extra Source Hub:
Undercode
