CVE-2000-1066 in FreeBSD
Summary
by MITRE
The getnameinfo function in FreeBSD 4.1.1 and earlier, and possibly other operating systems, allows a remote attacker to cause a denial of service via a long DNS hostname.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 09/02/2019
The getnameinfo function vulnerability in FreeBSD 4.1.1 and earlier versions represents a critical denial of service weakness that exploits improper input validation during DNS hostname resolution. This vulnerability resides in the system's network resolution capabilities and affects operating systems that implement the standard getnameinfo function for address-to-name resolution. The flaw manifests when the function processes excessively long DNS hostnames, causing the system to enter an infinite loop or consume excessive resources during hostname processing. The vulnerability operates at the network stack level where the getnameinfo function translates socket addresses into printable network host names and service names, making it a fundamental component in network communication infrastructure.
The technical implementation of this vulnerability stems from inadequate bounds checking within the getnameinfo function's hostname parsing logic. When a remote attacker crafts a specially formatted DNS query containing an abnormally long hostname string, the function fails to properly validate the input length before processing. This leads to memory allocation issues and potential stack overflow conditions that cause the system to become unresponsive or crash entirely. The vulnerability is particularly dangerous because it can be triggered through normal network operations without requiring authentication or special privileges. The attack vector typically involves sending malformed DNS responses or crafting malicious network packets that contain oversized hostname fields, which then propagate through the getnameinfo function's processing pipeline.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise entire network infrastructure. Systems running affected versions of FreeBSD become vulnerable to denial of service attacks that can render network services unavailable for extended periods, affecting critical applications and user access. The vulnerability affects not only the specific FreeBSD versions mentioned but likely other Unix-like operating systems that implement similar network resolution functions, making it a widespread concern across multiple platforms. Network administrators face the challenge of identifying vulnerable systems and implementing patches without disrupting ongoing operations, as the vulnerability can be exploited through legitimate network traffic.
Mitigation strategies for this vulnerability require immediate system updates and patches to address the underlying implementation flaws in the getnameinfo function. Organizations should prioritize upgrading to patched versions of FreeBSD and other affected operating systems while implementing network monitoring to detect suspicious hostname length patterns. Network segmentation and access controls can provide additional protection layers, though these measures do not eliminate the core vulnerability. The fix typically involves implementing proper input validation and length checking within the getnameinfo function to prevent processing of excessively long hostname strings. Security teams should also consider implementing rate limiting and connection monitoring to detect and prevent exploitation attempts, aligning with the principles of defensive security practices outlined in industry standards and frameworks.
This vulnerability aligns with CWE-122, which describes improper restriction of operations within a limited error handling scope, and demonstrates characteristics consistent with the attack patterns found in the MITRE ATT&CK framework under the T1498 technique for network denial of service. The weakness represents a classic example of how insufficient input validation can create exploitable conditions in system libraries, highlighting the importance of robust security testing and code review processes in network infrastructure components.