CVE-2002-0038 in IRIX
Summary
by MITRE
Vulnerability in the cache-limiting function of the unified name service daemon (nsd) in IRIX 6.5.4 through 6.5.11 allows remote attackers to cause a denial of service by forcing the cache to fill the disk.
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Analysis
by VulDB Data Team • 04/11/2019
The vulnerability identified as CVE-2002-0038 resides within the unified name service daemon (nsd) implementation in SGI IRIX operating systems version 6.5.4 through 6.5.11. This flaw specifically targets the cache-limiting functionality that governs how the name service daemon manages its internal cache storage. The nsd serves as a critical component in IRIX systems, providing name resolution services that bridge between domain names and their corresponding network addresses. When properly configured, this daemon handles requests for hostname resolution and maintains a cache of previously resolved entries to improve performance and reduce network overhead.
The technical flaw manifests in the cache management algorithm where the daemon fails to properly enforce size limitations on its cache storage. Under normal operating conditions, the nsd maintains a cache of resolved names to avoid repeated lookups and reduce system load. However, the vulnerability allows malicious actors to exploit the cache-limiting mechanism by sending specially crafted DNS queries or name resolution requests that cause the cache to grow beyond its intended capacity. This occurs because the daemon does not properly validate or restrict the number of entries that can be stored in the cache, nor does it implement adequate mechanisms to prevent cache exhaustion through controlled manipulation.
The operational impact of this vulnerability represents a significant denial of service condition that can completely disrupt network name resolution services on affected IRIX systems. When the cache fills the available disk space, the nsd daemon becomes unable to process new name resolution requests, effectively rendering the system incapable of performing hostname lookups. This disruption affects not only local applications that depend on name resolution but also network services that rely on proper DNS functionality. The vulnerability is particularly dangerous because it can be exploited remotely without requiring authentication or elevated privileges, making it accessible to any attacker with network access to the affected system.
The underlying cause of this vulnerability aligns with CWE-129, which addresses improper validation of buffer sizes and memory limits. This weakness in the nsd implementation demonstrates poor resource management practices where the system fails to implement adequate bounds checking for cache operations. From an adversarial perspective, this vulnerability maps to ATT&CK technique T1499.004, which covers network denial of service attacks targeting services through resource exhaustion. The attack vector is particularly effective because it leverages legitimate name resolution functionality to cause system-wide disruption, making detection difficult and exploitation straightforward for attackers familiar with DNS protocols and IRIX system internals.
Mitigation strategies for this vulnerability should include immediate implementation of system updates and patches provided by SGI for IRIX 6.5.4 through 6.5.11. Network administrators should consider implementing rate limiting mechanisms at the firewall level to restrict the number of DNS queries that can be processed from any single source within a given time period. Additionally, monitoring systems should be configured to track cache utilization levels and alert administrators when cache usage approaches critical thresholds. System administrators should also review and tighten cache configuration parameters to ensure that maximum cache sizes are properly enforced and that automatic cache cleanup mechanisms are operational. The most effective long-term solution involves upgrading to newer versions of IRIX that contain fixed implementations of the nsd daemon with proper cache management and resource limitation controls.