CVE-2018-6808 in NetScaler ADC
Summary
by MITRE
NetScaler ADC 10.5, 11.0, 11.1, and 12.0, and NetScaler Gateway 10.5, 11.0, 11.1, and 12.0 allow remote attackers to download arbitrary files on the target system.
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Analysis
by VulDB Data Team • 02/17/2023
The vulnerability identified as CVE-2018-6808 represents a critical arbitrary file download flaw affecting Citrix NetScaler Application Delivery Controller and NetScaler Gateway appliances across multiple versions including 10.5, 11.0, 11.1, and 12.0. This vulnerability resides within the web interface component of these security appliances and enables remote attackers to retrieve arbitrary files from the target system without proper authentication. The flaw stems from insufficient input validation and access control mechanisms within the file download functionality, allowing malicious actors to manipulate file paths and access sensitive system files that should remain protected. Such vulnerabilities are particularly dangerous as they can expose critical system components including configuration files, certificate stores, and potentially sensitive data stored on the appliance.
The technical implementation of this vulnerability involves a lack of proper sanitization of user-supplied input parameters that are used to construct file paths for download operations. Attackers can exploit this by crafting malicious requests that include directory traversal sequences or direct file references, bypassing the intended access controls. The flaw operates at the application layer and can be exploited through the web administration interface or API endpoints that handle file operations. This type of vulnerability is categorized under CWE-22 - Improper Limitation of a Pathname to a Restricted Directory and aligns with ATT&CK technique T1213.002 - Data from Information Repositories, specifically targeting the extraction of sensitive data from compromised systems. The vulnerability demonstrates a classic path traversal attack vector where the application fails to properly validate and sanitize file path inputs before processing them.
The operational impact of CVE-2018-6808 extends beyond simple unauthorized file access, potentially enabling attackers to extract critical system information that could facilitate further compromise of the network infrastructure. Successful exploitation could lead to the disclosure of administrative credentials, encryption keys, configuration files containing sensitive information, and other system artifacts that provide attackers with deeper insights into the target environment. This vulnerability particularly affects organizations that rely on Citrix NetScaler appliances for load balancing, application delivery, and secure access services, as these devices often serve as critical network gateways. The implications are severe for enterprise environments where these appliances protect access to internal resources, as attackers could potentially gain access to authentication mechanisms and sensitive corporate data. The vulnerability can result in complete compromise of the appliance and potentially provide attackers with a foothold for lateral movement within the network infrastructure.
Organizations affected by CVE-2018-6808 should implement immediate mitigations including applying the official Citrix security patches released for the affected versions, implementing network segmentation to restrict access to the appliance web interfaces, and monitoring for suspicious file download activities. Network administrators should also consider implementing web application firewalls to detect and block malicious path traversal attempts, and conduct thorough audits of system configurations to identify any unauthorized access that may have occurred. The vulnerability highlights the importance of proper input validation and access control implementation in web applications, particularly those handling sensitive system operations. Security teams should also perform regular vulnerability assessments and penetration testing to identify similar weaknesses in other network components, as this vulnerability demonstrates how insufficient input validation can lead to critical information disclosure. Additionally, organizations should establish robust incident response procedures to quickly detect and respond to exploitation attempts, as early detection is crucial for minimizing potential damage from such vulnerabilities.