CVE-2015-2838 in Netscaler
Summary
by MITRE
Cross-site request forgery (CSRF) vulnerability in Nitro API in Citrix NetScaler before 10.5 build 52.3nc allows remote attackers to hijack the authentication of administrators for requests that execute arbitrary commands as nsroot via shell metacharacters in the file_name JSON member in params/xen_hotfix/0 to nitro/v1/config/xen_hotfix.
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Analysis
by VulDB Data Team • 11/29/2024
The CVE-2015-2838 vulnerability represents a critical cross-site request forgery flaw within the Nitro API of Citrix NetScaler appliances running versions prior to 10.5 build 52.3nc. This vulnerability resides in the administrative interface of the NetScaler platform, specifically within the xen_hotfix configuration endpoint. The flaw enables remote attackers to exploit the system's authentication mechanisms by crafting malicious requests that appear to originate from legitimate administrative sessions, thereby bypassing normal security controls and executing arbitrary commands with the highest possible privileges.
The technical implementation of this vulnerability occurs through manipulation of the file_name JSON parameter within the params/xen_hotfix/0 endpoint of the Nitro API. Attackers can inject shell metacharacters into the file_name member, which then gets processed by the underlying system without proper sanitization or validation. This allows for command injection attacks that can execute arbitrary code with the nsroot administrative privileges, effectively granting attackers complete control over the NetScaler appliance. The vulnerability is particularly dangerous because it operates at the configuration level where commands are executed directly on the system shell, bypassing traditional application-level security measures.
The operational impact of this vulnerability is severe and far-reaching for organizations relying on Citrix NetScaler appliances for their network security infrastructure. Successful exploitation can lead to complete compromise of the appliance, enabling attackers to modify network configurations, intercept traffic, disable security features, or establish persistent backdoors. The nsroot account provides the highest level of administrative access, making this vulnerability particularly attractive to threat actors targeting enterprise network infrastructure. Organizations may experience service disruption, data breaches, or complete network isolation if attackers leverage this vulnerability to gain unauthorized access to their critical infrastructure.
Mitigation strategies for CVE-2015-2838 should focus on immediate patching of affected NetScaler appliances to version 10.5 build 52.3nc or later, which includes proper CSRF token validation and input sanitization. Organizations should also implement network segmentation to limit access to the Nitro API endpoints, enforce strict firewall rules restricting administrative access, and deploy intrusion detection systems to monitor for suspicious API activity. The vulnerability aligns with CWE-352, which specifically addresses cross-site request forgery weaknesses, and maps to ATT&CK technique T1059 for command and scripting interpreter usage, highlighting the critical nature of preventing unauthorized command execution at the system level. Regular security assessments and monitoring of administrative API endpoints should be implemented to detect and prevent similar vulnerabilities in the future.