CVE-2020-15180: MariaDB mysql-wsrep RCE Vulnerability

CVE-2020-15180 Overview

A critical command injection vulnerability was discovered in the mysql-wsrep component of MariaDB. The flaw exists due to a lack of input sanitization in the wsrep_sst_method parameter, which allows remote attackers to inject and execute arbitrary commands on Galera cluster nodes. This vulnerability poses a severe threat to database infrastructure by compromising system confidentiality, integrity, and availability.

Critical Impact

Remote attackers can execute arbitrary commands on Galera cluster nodes without authentication, potentially leading to complete system compromise across clustered database environments.

Affected Products

• MariaDB versions before 10.1.47, 10.2.34, 10.3.25, 10.4.15, and 10.5.6
• Debian Linux 9.0 and 10.0
• Percona XtraDB Cluster (affected versions)
• Galera Cluster for MySQL (affected versions)

Discovery Timeline

• 2021-05-27 - CVE CVE-2020-15180 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2020-15180

Vulnerability Analysis

This command injection vulnerability resides in the mysql-wsrep component, which is responsible for State Snapshot Transfer (SST) operations in Galera-based database clusters. The wsrep_sst_method configuration parameter accepts user-controlled input that is not properly sanitized before being passed to shell commands during SST operations.

The vulnerability is particularly dangerous in clustered database environments where multiple nodes synchronize state. An attacker who can influence the SST method configuration can inject malicious shell commands that execute with the privileges of the MariaDB service user. This can lead to complete compromise of database cluster nodes, data exfiltration, ransomware deployment, or lateral movement within the network.

The attack requires network access but does not need user interaction or prior authentication, making it exploitable in scenarios where the database cluster is accessible from untrusted networks.

Root Cause

The root cause is improper input validation (CWE-20) and command injection (CWE-77) in the wsrep_sst_method handling code. The SST method parameter is incorporated into shell commands without adequate sanitization or escaping, allowing shell metacharacters to break out of the intended command context and execute attacker-controlled commands.

Attack Vector

The attack vector is network-based, targeting MariaDB Galera cluster deployments. An attacker can exploit this vulnerability by:

1. Gaining access to a network where the Galera cluster is deployed
2. Crafting a malicious wsrep_sst_method value containing shell command injection payloads
3. Triggering an SST operation that processes the unsanitized input
4. Achieving arbitrary command execution on cluster nodes

The vulnerability is exploitable remotely without authentication, though the attack complexity is high due to the need for specific cluster configurations and timing. Since the scope is changed, successful exploitation can impact resources beyond the vulnerable component itself, potentially affecting the entire cluster infrastructure.

Detection Methods for CVE-2020-15180

Indicators of Compromise

• Unusual process spawning from MariaDB or MySQL service processes, particularly shell interpreters (/bin/sh, /bin/bash)
• Unexpected network connections originating from database server processes
• Anomalous modifications to wsrep_sst_method configuration values containing shell metacharacters (;, |, $(), backticks)
• Log entries showing SST operations with malformed or suspicious method names

Detection Strategies

• Monitor database configuration changes, specifically the wsrep_sst_method parameter, for unexpected or malicious values
• Implement process monitoring on database servers to detect child processes spawned by MariaDB that are not typical database operations
• Deploy network-based intrusion detection rules to identify exploitation attempts targeting Galera SST functionality
• Enable and analyze MariaDB audit logs for suspicious configuration queries or changes

Monitoring Recommendations

• Configure SentinelOne agents on all database cluster nodes to detect anomalous process execution chains
• Set up alerts for any modification attempts to Galera cluster configuration files
• Monitor for outbound network connections from database processes to unexpected destinations
• Implement file integrity monitoring on MariaDB configuration directories

How to Mitigate CVE-2020-15180

Immediate Actions Required

• Upgrade MariaDB to patched versions: 10.1.47, 10.2.34, 10.3.25, 10.4.15, or 10.5.6 and later
• Restrict network access to Galera cluster communication ports using firewall rules
• Audit current wsrep_sst_method configuration values across all cluster nodes
• Implement network segmentation to isolate database clusters from untrusted networks

Patch Information

MariaDB has released security updates addressing this vulnerability. Administrators should upgrade to the following minimum versions:

• MariaDB 10.1.47 or later (for 10.1.x branch)
• MariaDB 10.2.34 or later (for 10.2.x branch)
• MariaDB 10.3.25 or later (for 10.3.x branch)
• MariaDB 10.4.15 or later (for 10.4.x branch)
• MariaDB 10.5.6 or later (for 10.5.x branch)

For Debian-based systems, refer to Debian Security Advisory DSA-4776 and the Debian LTS Announcement. Percona XtraDB Cluster users should consult the Percona Blog on CVE-2020-15180 for specific guidance. Gentoo users should apply GLSA 202011-14.

Workarounds

• If immediate patching is not possible, restrict Galera cluster communication to trusted internal networks only
• Disable SST operations temporarily if not actively required for cluster maintenance
• Implement strict firewall rules to limit access to ports 4567 (Galera cluster communication), 4568 (IST), and 4444 (SST)
• Use configuration management tools to enforce and monitor approved wsrep_sst_method values

# Example: Restrict Galera ports to trusted cluster nodes only
iptables -A INPUT -p tcp --dport 4567 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 4568 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 4444 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 4567 -j DROP
iptables -A INPUT -p tcp --dport 4568 -j DROP
iptables -A INPUT -p tcp --dport 4444 -j DROP