CVE-2020-11800 Overview
CVE-2020-11800 is a critical remote code execution vulnerability affecting Zabbix Server versions 2.2.x, 3.0.x before 3.0.31, and 3.2. This vulnerability allows remote attackers to execute arbitrary code on vulnerable Zabbix Server installations without requiring authentication, potentially leading to complete system compromise.
Critical Impact
Remote attackers can execute arbitrary code on vulnerable Zabbix Server installations, potentially gaining full control over monitoring infrastructure and connected systems.
Affected Products
- Zabbix Server versions 2.2.x (all versions)
- Zabbix Server versions 3.0.x before 3.0.31
- Zabbix Server version 3.2.0
- openSUSE Backports SLE 15.0 SP1 and SP2
- openSUSE Leap 15.1 and 15.2
- Debian Linux 9.0
Discovery Timeline
- 2020-10-07 - CVE-2020-11800 published to NVD
- 2024-11-21 - Last updated in NVD database
Technical Details for CVE-2020-11800
Vulnerability Analysis
This vulnerability enables remote code execution in Zabbix Server, a widely-deployed enterprise monitoring solution. The flaw allows unauthenticated remote attackers to execute arbitrary code on the server, which is particularly dangerous given Zabbix Server's role as a central monitoring hub with access to numerous systems across an organization's infrastructure.
The vulnerability is exploitable over the network without any user interaction or authentication requirements. Successful exploitation results in complete compromise of confidentiality, integrity, and availability of the affected system. Given Zabbix Server's typical deployment in enterprise environments with elevated privileges for system monitoring, attackers could leverage this access to pivot to other systems on the network.
Root Cause
The vulnerability stems from improper input validation in Zabbix Server's processing of incoming requests. The server fails to properly sanitize or validate certain input data before processing, allowing attackers to inject and execute arbitrary code. This represents a fundamental input validation error that enables code injection attacks.
Attack Vector
The attack is network-based, allowing remote exploitation without authentication. An attacker can send specially crafted requests to a vulnerable Zabbix Server instance to trigger the vulnerability. The attack does not require any user interaction, making it particularly dangerous for internet-exposed or inadequately segmented Zabbix deployments.
The exploitation process involves:
- Identifying a vulnerable Zabbix Server instance (versions 2.2.x, 3.0.x before 3.0.31, or 3.2.0)
- Sending malicious requests to the Zabbix Server service
- The server processes the malicious input without proper validation
- Arbitrary code execution occurs with the privileges of the Zabbix Server process
Technical details regarding the specific exploitation mechanism can be found in the Zabbix Security Advisory.
Detection Methods for CVE-2020-11800
Indicators of Compromise
- Unexpected outbound connections from Zabbix Server processes to unknown IP addresses
- Unusual process spawning from the Zabbix Server daemon (zabbix_server)
- Unexpected modifications to Zabbix configuration files or databases
- Anomalous CPU or memory usage patterns on Zabbix Server hosts
Detection Strategies
- Monitor network traffic to and from Zabbix Server instances for anomalous patterns or connections to known malicious infrastructure
- Implement file integrity monitoring on Zabbix Server binaries and configuration files
- Review Zabbix Server logs for unusual error messages or access patterns
- Deploy network intrusion detection signatures to identify exploitation attempts targeting Zabbix services
Monitoring Recommendations
- Enable comprehensive logging on Zabbix Server instances and forward logs to a centralized SIEM
- Monitor for unexpected child processes spawned by zabbix_server processes
- Implement behavioral analysis to detect abnormal Zabbix Server activity patterns
- Set up alerts for any unauthorized access attempts or configuration changes
How to Mitigate CVE-2020-11800
Immediate Actions Required
- Upgrade Zabbix Server to version 3.0.31 or later immediately
- If running version 3.2.0, upgrade to a patched release as specified by Zabbix
- Restrict network access to Zabbix Server ports to trusted hosts only
- Implement network segmentation to limit potential lateral movement if compromise occurs
Patch Information
Zabbix has released patches addressing this vulnerability. Organizations running affected versions should upgrade to Zabbix Server version 3.0.31 or later. Detailed patch information is available through the Zabbix Issue Tracker and the Zabbix Security Advisory.
For Debian-based systems, refer to the Debian LTS Security Notice for distribution-specific patches. openSUSE users should consult the openSUSE Security Announcement for applicable updates.
Workarounds
- Restrict network access to Zabbix Server using firewall rules to allow connections only from trusted IP addresses
- Place Zabbix Server behind a VPN or jump host to limit exposure
- Implement network segmentation to isolate Zabbix infrastructure from critical systems
- Monitor and log all access to Zabbix Server services pending the application of patches
# Example: Restrict Zabbix Server access using iptables
# Allow Zabbix agent connections only from trusted monitoring network
iptables -A INPUT -p tcp --dport 10051 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 10051 -j DROP
# Allow web interface access only from management network
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
