CVE-2021-44520 in XenMobile
Summary
by MITRE • 04/13/2022
In Citrix XenMobile Server through 10.12 RP9, there is an Authenticated Command Injection vulnerability, leading to remote code execution with root privileges.
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Analysis
by VulDB Data Team • 04/18/2022
The CVE-2021-44520 vulnerability represents a critical authenticated command injection flaw within Citrix XenMobile Server versions up to 10.12 RP9, presenting a severe security risk that can lead to complete system compromise. This vulnerability exists in the server's handling of user input within specific administrative functions, where insufficient validation allows attackers with legitimate administrative credentials to inject malicious commands that execute with root privileges. The flaw stems from improper sanitization of input parameters that are subsequently used in system commands without adequate escaping or filtering mechanisms. Security researchers identified that the vulnerability manifests when authenticated users interact with certain administrative APIs or web interfaces that process user-supplied data without proper input validation.
The technical implementation of this vulnerability follows a classic command injection pattern where user-controllable input is directly incorporated into system command execution contexts. Attackers can exploit this by crafting malicious payloads that, when processed by the vulnerable server, result in arbitrary command execution. The authentication requirement means that an attacker must first obtain valid administrative credentials, which could be acquired through credential theft, social engineering, or other initial compromise techniques. However, once authenticated, the attacker gains the ability to execute commands with the highest possible privileges, effectively providing complete control over the target system. This vulnerability aligns with CWE-77 and CWE-88 categories, which specifically address command injection flaws where user input is improperly handled in command construction and execution contexts.
The operational impact of CVE-2021-44520 extends far beyond simple privilege escalation, as it enables attackers to achieve persistent access to enterprise infrastructure. Successful exploitation allows adversaries to install backdoors, exfiltrate sensitive data, modify system configurations, and establish covert communication channels. The root privilege execution capability means that attackers can bypass traditional security controls and access all system resources without restriction. Organizations using Citrix XenMobile Server are particularly vulnerable since this platform often serves as a central management point for mobile device management, making it a prime target for attackers seeking to compromise enterprise mobile environments. The vulnerability can be leveraged to create persistent access points within networks, potentially enabling lateral movement and broader compromise of connected systems.
Mitigation strategies for CVE-2021-44520 should focus on immediate patching of affected systems with the vendor-provided security updates. Organizations should implement strict access controls and principle of least privilege to limit the number of users with administrative credentials. Network segmentation and monitoring of administrative API calls can help detect anomalous command execution patterns. Security teams should also consider implementing web application firewalls and input validation controls to prevent similar vulnerabilities from being exploited in other applications. The vulnerability demonstrates the importance of proper input validation and output encoding as outlined in the OWASP Top Ten and MITRE ATT&CK framework's command and control techniques. Organizations should conduct comprehensive vulnerability assessments to identify other potential command injection vulnerabilities within their infrastructure and establish incident response procedures to handle potential exploitation attempts.