CVE-2022-43553: Ui EdgeMAX EdgeRouter Firmware RCE Flaw

CVE-2022-43553 Overview

CVE-2022-43553 is a remote code execution vulnerability affecting Ubiquiti EdgeRouters running firmware version 2.0.9-hotfix.4 and earlier. This privilege escalation flaw allows a malicious actor with an operator account to execute arbitrary administrator commands, effectively bypassing the intended privilege separation in the device's access control system.

Critical Impact

Authenticated attackers with low-privilege operator accounts can escalate to administrative privileges and execute arbitrary commands, potentially leading to complete device compromise and network infrastructure takeover.

Affected Products

• Ubiquiti EdgeMAX EdgeRouter Firmware versions prior to 2.0.9-hotfix.5
• Ubiquiti EdgeMAX EdgeRouter Firmware version 2.0.9 (base)
• Ubiquiti EdgeMAX EdgeRouter Firmware versions 2.0.9-hotfix.1 through 2.0.9-hotfix.4
• Ubiquiti EdgeMAX EdgeRouter Hardware

Discovery Timeline

• 2022-12-05 - CVE-2022-43553 published to NVD
• 2025-04-24 - Last updated in NVD database

Technical Details for CVE-2022-43553

Vulnerability Analysis

This vulnerability represents a classic privilege escalation attack vector in network infrastructure devices. The flaw exists in the EdgeRouter's command execution mechanism, where insufficient validation of user privileges allows operator-level accounts to execute commands that should be restricted to administrator accounts only.

The vulnerability is particularly concerning because EdgeRouters are commonly deployed as edge network devices, often serving as the first line of defense for enterprise and small business networks. Successful exploitation could allow an attacker to modify firewall rules, intercept network traffic, pivot to internal systems, or establish persistent backdoor access.

The attack requires network access and valid operator credentials, but once these prerequisites are met, exploitation is straightforward with no user interaction required. The impact is severe, potentially affecting the confidentiality, integrity, and availability of both the device and the network it protects.

Root Cause

The vulnerability stems from CWE-250 (Execution with Unnecessary Privileges). The EdgeRouter firmware fails to properly enforce privilege boundaries between operator and administrator account types. When operator accounts execute certain commands, the system improperly elevates privileges to administrative level, allowing execution of commands that should be restricted.

This design flaw in the privilege separation mechanism means that the principle of least privilege is not correctly implemented, enabling authenticated users to perform actions beyond their intended authorization scope.

Attack Vector

The attack is conducted remotely over the network. An attacker who has obtained or been assigned operator-level credentials can leverage this vulnerability to execute administrator commands without proper authorization. The attack flow involves:

1. Authenticating to the EdgeRouter with operator account credentials
2. Identifying commands or interfaces that fail to validate privilege levels
3. Executing administrator-level commands through the vulnerable interface
4. Gaining full administrative control over the device

The vulnerability does not require user interaction and can be exploited reliably once authentication is achieved with operator credentials.

Detection Methods for CVE-2022-43553

Indicators of Compromise

• Unexpected configuration changes on EdgeRouter devices, particularly firewall rules, routing tables, or user accounts
• Operator accounts executing administrative functions or accessing restricted areas
• Unusual command execution patterns in device logs showing privilege boundary violations
• New administrator accounts created without authorization
• Modified firmware or persistent configuration changes not initiated by legitimate administrators

Detection Strategies

• Monitor EdgeRouter system logs for commands executed by operator accounts that should require administrator privileges
• Implement log forwarding to a centralized SIEM to capture and analyze authentication and command execution events
• Regularly audit user accounts and privilege assignments on network infrastructure devices
• Deploy network monitoring to detect anomalous management traffic to EdgeRouter devices

Monitoring Recommendations

• Enable verbose logging on EdgeRouters and forward logs to a secure, centralized logging platform
• Configure alerts for configuration changes and account modifications
• Implement baseline monitoring for normal administrative activity patterns
• Review device firmware versions across the network to identify vulnerable installations

How to Mitigate CVE-2022-43553

Immediate Actions Required

• Upgrade all affected EdgeRouter devices to firmware version 2.0.9-hotfix.5 or later immediately
• Audit all operator and administrator accounts for unauthorized changes or suspicious activity
• Review device configurations for any unauthorized modifications
• Restrict network access to EdgeRouter management interfaces using ACLs or firewall rules
• Implement multi-factor authentication where supported for management access

Patch Information

Ubiquiti has addressed this vulnerability in EdgeRouter firmware version 2.0.9-hotfix.5 and later releases. Organizations should download the updated firmware from the official Ubiquiti download portal and apply it to all affected devices. For detailed patch information, refer to the Ubiquiti Security Advisory Bulletin 026.

Workarounds

• Limit operator account usage and prefer administrator accounts with proper access controls until patching is complete
• Restrict management interface access to trusted networks or specific IP addresses only
• Disable remote management access if not required for operations
• Implement network segmentation to isolate management plane traffic from general network traffic
• Monitor operator account activity closely until firmware updates can be applied

# Example: Restrict management access to specific subnet
configure
set service gui listen-address 192.168.1.1
set firewall name MGMT_RESTRICT rule 10 action accept
set firewall name MGMT_RESTRICT rule 10 source address 10.0.0.0/24
set firewall name MGMT_RESTRICT rule 10 destination port 443
set firewall name MGMT_RESTRICT rule 20 action drop
set firewall name MGMT_RESTRICT rule 20 destination port 443
commit
save