CVE-1999-1349 in Omni-nfs X Enterprise
Summary
by MITRE
NFS daemon (nfsd.exe) for Omni-NFS/X 6.1 allows remote attackers to cause a denial of service (resource exhaustion) via certain packets, possibly with the Urgent (URG) flag set, to port 111.
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Analysis
by VulDB Data Team • 04/19/2026
The vulnerability described in CVE-1999-1349 represents a critical denial of service weakness in the Omni-NFS/X 6.1 network file sharing implementation. This flaw specifically targets the NFS daemon component known as nfsd.exe which operates on TCP port 111, the standard port for the Sun RPC portmapper service. The vulnerability exploits a weakness in how the daemon processes incoming network packets, particularly those with the urgent flag set, leading to resource exhaustion conditions that effectively render the system unavailable to legitimate users. This type of vulnerability falls under the category of resource exhaustion attacks as classified by CWE-400, where malicious actors can consume system resources such as memory, CPU cycles, or file descriptors to prevent normal system operation.
The technical implementation of this vulnerability demonstrates how network protocols can be manipulated to exploit implementation flaws in server-side applications. When the nfsd.exe daemon receives specially crafted packets with the urgent flag set, it fails to properly handle the packet structure, causing the system to allocate excessive resources or enter an infinite loop. This behavior is particularly concerning because port 111 serves as the primary registration point for RPC services, making it a high-value target for attackers seeking to disrupt network operations. The attack vector requires only network access to the target system, making it relatively easy to exploit and potentially scalable across multiple systems. The vulnerability represents a classic example of improper input validation and resource management as outlined in CWE-252, where the system fails to properly validate incoming data before processing it.
From an operational impact perspective, this vulnerability creates significant business disruption potential for organizations relying on NFS services. When exploited successfully, the denial of service condition can affect not just the specific NFS daemon but potentially the entire file sharing infrastructure, impacting multiple users and applications that depend on network storage. The resource exhaustion can lead to cascading failures where system performance degrades substantially, applications become unresponsive, and legitimate users lose access to critical data services. This vulnerability particularly affects enterprise environments where network file systems are extensively used for data sharing and collaborative work. The impact extends beyond immediate service disruption to include potential data integrity concerns and increased administrative overhead as system administrators must respond to the attack and restore normal operations.
Organizations should implement multiple layers of mitigation strategies to address this vulnerability effectively. Network segmentation and access control measures should be deployed to limit access to port 111 to trusted sources only, reducing the attack surface available to potential attackers. Firewalls and intrusion detection systems should be configured to monitor for unusual packet patterns, particularly those with urgent flags set, and alert administrators to potential exploitation attempts. Regular system updates and patches should be applied immediately upon availability, as this vulnerability was likely addressed in subsequent releases of the Omni-NFS software. The mitigation approach aligns with ATT&CK technique T1499.004 for network denial of service attacks, emphasizing the importance of network monitoring and access control measures. Additionally, system administrators should implement resource monitoring to detect unusual consumption patterns that may indicate exploitation attempts, and establish incident response procedures specifically for handling denial of service attacks targeting network services. Organizations should also consider implementing redundant systems and failover mechanisms to minimize the impact of successful exploitation attempts on overall business operations.