CVE-2013-4376 in X2Go Server
Summary
by MITRE
The setgid wrapper libx2go-server-db-sqlite3-wrapper.c in X2Go Server before 4.0.0.2 allows remote attackers to execute arbitrary code via unspecified vectors, relate to the path to libx2go-server-db-sqlite3-wrapper.pl.
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Analysis
by VulDB Data Team • 01/11/2022
The vulnerability identified as CVE-2013-4376 affects the X2Go Server software ecosystem, specifically targeting the setgid wrapper component responsible for database operations. This flaw exists within the libx2go-server-db-sqlite3-wrapper.c file and represents a critical security weakness that enables remote code execution capabilities. The vulnerability stems from improper handling of the path to the Perl wrapper script libx2go-server-db-sqlite3-wrapper.pl, creating an exploitable condition that adversaries can leverage from remote locations. The X2Go Server is widely used for remote desktop solutions and terminal services, making this vulnerability particularly concerning for organizations relying on remote access infrastructure. The setgid functionality implies that the wrapper operates with elevated privileges, amplifying the potential impact of exploitation. This type of vulnerability falls under CWE-276, which addresses improper privileges, and relates to CWE-78, concerning OS command injection, as the path handling issue could enable command execution through crafted input.
The technical implementation of this vulnerability involves the setgid wrapper mechanism that executes database operations with elevated permissions. When the wrapper processes input or handles paths to the Perl script, it fails to properly validate or sanitize the file path specification. This creates an opportunity for attackers to manipulate the execution flow by controlling the path resolution process. The vulnerability's remote exploitability indicates that attackers do not require local access to the system, making it particularly dangerous for network-facing installations. The path traversal or injection aspects of the flaw allow malicious actors to potentially redirect execution to arbitrary code locations, effectively bypassing normal access controls and privilege boundaries. The attack vector likely involves sending specially crafted data through network interfaces that the X2Go server accepts, triggering the vulnerable code path that leads to arbitrary code execution.
Organizations utilizing X2Go Server versions prior to 4.0.0.2 face significant operational risks from this vulnerability, as it provides a direct pathway for remote attackers to gain unauthorized system access. The impact extends beyond simple privilege escalation to full system compromise, since the setgid wrapper executes with elevated permissions. This vulnerability directly relates to the ATT&CK technique T1068, which involves exploiting legitimate credentials and privileges to gain system access, and T1059, concerning command and scripting interpreters. The attack surface includes any system running vulnerable X2Go Server implementations, particularly those exposed to untrusted networks or internet-facing services. Organizations may experience unauthorized data access, system modification, or complete system takeover, with potential for lateral movement within networks where the server operates. The vulnerability's exploitation could result in persistent backdoors, data exfiltration, or disruption of remote desktop services that many organizations depend upon for business continuity.
Mitigation strategies for CVE-2013-4376 primarily involve immediate patching of X2Go Server installations to version 4.0.0.2 or later, which addresses the path handling issues in the setgid wrapper. System administrators should also implement network segmentation to limit access to X2Go server components, particularly restricting access to the specific ports and services that expose the vulnerable functionality. Additional defensive measures include monitoring for suspicious network traffic patterns that might indicate exploitation attempts, implementing proper input validation for all user-supplied data, and conducting regular security assessments of remote desktop infrastructure. The principle of least privilege should be enforced by limiting the permissions of the setgid wrapper components and ensuring that only necessary processes can execute with elevated privileges. Organizations should also consider implementing intrusion detection systems to monitor for potential exploitation attempts and establish incident response procedures specifically addressing remote code execution vulnerabilities in remote desktop solutions. Security teams must perform comprehensive vulnerability assessments across all X2Go installations and ensure proper patch management processes are in place to prevent similar issues in the future.