CVE-2011-0183 in Mac OS X
Summary
by MITRE
Libinfo in Apple Mac OS X before 10.6.7 does not properly handle an unspecified integer field in an NFS RPC packet, which allows remote attackers to cause a denial of service (lockd, statd, mountd, or portmap outage) via a crafted packet, related to an "integer truncation issue."
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Analysis
by VulDB Data Team • 01/19/2025
The vulnerability described in CVE-2011-0183 represents a critical integer truncation flaw within the libinfo library component of Apple Mac OS X versions prior to 10.6.7. This issue specifically affects the Network File System (NFS) implementation where the system fails to properly validate integer fields within Remote Procedure Call (RPC) packets. The flaw exists at the protocol parsing level where an unspecified integer field in NFS RPC communications is not correctly handled, creating a potential attack vector that can be exploited by remote malicious actors.
The technical nature of this vulnerability stems from improper input validation within the NFS RPC processing code. When the libinfo library receives crafted NFS RPC packets containing malformed integer values, the system's handling mechanism fails to properly truncate or validate these values, leading to unexpected behavior in the underlying NFS services. This integer truncation issue affects multiple core NFS daemon processes including lockd, statd, mountd, and portmap services that are essential for network file sharing operations. The vulnerability operates at the kernel level network stack processing, making it particularly dangerous as it can disrupt fundamental system services without requiring local system access or elevated privileges.
The operational impact of this vulnerability is significant as it enables remote attackers to execute denial of service attacks against affected systems. When exploited, the crafted NFS RPC packets cause the targeted NFS services to enter unstable states, resulting in complete outages of network file sharing capabilities. The disruption affects not just file access but can also impact system stability and availability of networked applications that depend on NFS services. This vulnerability particularly affects enterprise environments where network file sharing is critical for business operations, as it can be leveraged to create service interruptions that may persist until system reboot or manual service restart. The attack requires only network access to the affected system and does not necessitate authentication or special privileges, making it particularly dangerous in networked environments.
Security practitioners should consider this vulnerability in the context of the CWE-190 weakness category which covers integer overflow and unsigned integer overflow conditions. The ATT&CK framework categorizes this as a denial of service attack vector under the T1499.004 technique for network denial of service, while also relating to T1071.004 for application layer protocol manipulation. Organizations should implement immediate mitigations including applying the official Apple security updates that address this specific integer truncation issue in the libinfo library. Network segmentation and firewall rules can provide temporary protection by blocking NFS RPC traffic from untrusted networks, though this approach does not eliminate the underlying vulnerability. Regular system patching and monitoring for similar integer handling issues in network services remain crucial defensive measures. The vulnerability also highlights the importance of proper input validation in network protocol implementations and serves as a reminder of the critical nature of maintaining up-to-date system security patches to prevent exploitation of such fundamental protocol handling flaws.