CVE-2003-0211 in xinetd
Summary
by MITRE
Memory leak in xinetd 2.3.10 allows remote attackers to cause a denial of service (memory consumption) via a large number of rejected connections.
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Analysis
by VulDB Data Team • 10/20/2024
The vulnerability identified as CVE-2003-0211 represents a critical memory management flaw within the xinetd superdaemon version 2.3.10 that enables remote attackers to execute denial of service attacks through excessive connection handling. This issue stems from improper memory allocation and deallocation mechanisms within the service management framework that processes incoming connection requests. The vulnerability specifically manifests when xinetd encounters a large volume of rejected connections, causing the daemon to continuously allocate memory without properly releasing it, leading to progressive memory exhaustion. The affected xinetd version operates as a central service manager that handles multiple network services, making it a prime target for exploitation due to its critical role in system network accessibility. This memory leak vulnerability directly impacts the availability of network services by consuming system resources until the daemon becomes unresponsive or crashes entirely. The flaw operates at the application layer of the network stack, where xinetd processes incoming connection requests and manages service availability, creating a persistent resource depletion scenario that can be easily triggered by remote adversaries. According to CWE classification, this vulnerability maps to CWE-401: Improper Release of Memory and CWE-119: Improper Access of Resources, highlighting the core issues of memory management failure and resource access control. The attack vector leverages the network service architecture where remote attackers can simply establish multiple connection attempts that are subsequently rejected by the system, triggering the memory allocation cycle without proper cleanup. The operational impact extends beyond simple service disruption as the memory leak can eventually consume all available system memory, affecting other running processes and potentially causing complete system instability. This vulnerability aligns with ATT&CK technique T1499.004: Endpoint Denial of Service, which specifically targets resource exhaustion through improper handling of connection requests and service management. The memory consumption pattern creates a gradual degradation of system performance that may not be immediately apparent to administrators, making detection and mitigation more challenging. Organizations running vulnerable xinetd versions face significant risk as this flaw can be exploited without requiring special privileges or complex attack vectors. The vulnerability exists in the service management logic where connection handling routines fail to properly manage memory allocation for connection tracking structures. When rejected connections are processed, the daemon allocates memory for connection state tracking but fails to release this memory when the connection is ultimately rejected, creating a cumulative memory leak. The flaw demonstrates poor resource management practices in the daemon's connection handling code, where temporary connection data structures are not properly deallocated after use. The impact is particularly severe in high-traffic environments where the memory leak can compound rapidly, leading to system crashes or complete service unavailability. This vulnerability highlights the importance of proper memory management in long-running network services and the potential for seemingly benign operations to cause catastrophic system failures. The security implications extend to service availability and system stability, as the memory leak can be sustained over time without immediate detection, making it a stealthy but effective denial of service mechanism. Mitigation strategies should include immediate patching of xinetd to versions that address the memory management issues, implementing connection rate limiting to prevent exploitation, and monitoring system memory consumption for unusual patterns. System administrators should also consider implementing intrusion detection systems that can identify anomalous connection patterns indicative of this specific vulnerability exploitation. The vulnerability serves as a reminder of the critical importance of proper resource management in network services and the potential for memory leaks to create persistent security risks that can be exploited for denial of service attacks. Organizations should implement regular security assessments of their service management frameworks to identify similar memory management flaws that could be exploited in similar ways. The incident underscores the need for robust memory management practices in system software, particularly in critical infrastructure components like superdaemons that handle multiple concurrent connections. Proper input validation and resource cleanup procedures should be implemented to prevent such vulnerabilities from occurring in future software development cycles. This vulnerability demonstrates how network service management can become a vector for resource exhaustion attacks when proper memory management practices are not followed, emphasizing the importance of secure coding practices in system-level software components.