CVE-2008-5133 in OpenSolaris
Summary
by MITRE
ipnat in IP Filter in Sun Solaris 10 and OpenSolaris before snv_96, when running on a DNS server with Network Address Translation (NAT) configured, improperly changes the source port of a packet when the destination port is the DNS port, which allows remote attackers to bypass an intended CVE-2008-1447 protection mechanism and spoof the responses to DNS queries sent by named.
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Analysis
by VulDB Data Team • 05/25/2025
The vulnerability identified as CVE-2008-5133 represents a critical flaw in the IP Filter implementation within Sun Solaris 10 and OpenSolaris systems, specifically affecting versions prior to snv_96. This issue manifests when the system operates as a DNS server with Network Address Translation (NAT) configured, creating a dangerous condition where the source port of packets is incorrectly modified during DNS query processing. The flaw directly undermines the security mechanisms designed to protect against unauthorized DNS response spoofing, fundamentally compromising the integrity of DNS communications on affected systems.
The technical root cause of this vulnerability lies in the improper handling of packet source port modification within the ipnat component of IP Filter. When DNS queries are processed through NAT configurations, the system fails to maintain proper source port consistency for packets destined to the DNS port, creating a scenario where malicious actors can exploit this behavior to manipulate DNS responses. This flaw specifically impacts the CVE-2008-1447 protection mechanism, which was designed to prevent DNS spoofing attacks by ensuring proper source port validation during DNS query processing. The vulnerability operates at the network layer, affecting how packets are translated and routed through NAT configurations, making it particularly dangerous in environments where DNS services are critical to system operations.
The operational impact of CVE-2008-5133 extends beyond simple DNS spoofing capabilities, as it represents a significant weakening of the network security posture for affected Solaris systems. Attackers can leverage this vulnerability to forge DNS responses, potentially redirecting network traffic to malicious destinations, intercepting sensitive communications, or disrupting critical DNS-based services. The vulnerability's exploitation requires a specific configuration involving DNS servers running with NAT, but this combination is common in enterprise environments, making the threat widespread. Systems utilizing this configuration face elevated risk of man-in-the-middle attacks, where attackers can manipulate DNS responses to redirect users to compromised websites or intercept communications intended for legitimate services.
From a cybersecurity perspective, this vulnerability aligns with CWE-129, which addresses improper handling of input validation in network security contexts, and demonstrates characteristics consistent with ATT&CK technique T1071.004 for application layer protocol manipulation. The flaw essentially creates a bypass mechanism that undermines the intended security controls, allowing attackers to circumvent protection measures that were specifically designed to address DNS-related threats. Organizations running vulnerable Solaris systems face potential data exfiltration, service disruption, and compromise of network integrity, as the vulnerability enables attackers to effectively impersonate legitimate DNS servers within the network. Mitigation efforts should prioritize immediate patching of affected systems to address the ipnat implementation flaw, while network administrators should consider implementing additional monitoring for anomalous DNS traffic patterns that could indicate exploitation attempts.
The broader implications of this vulnerability highlight the complexity of network security implementations in operating systems, where interactions between different security components can create unexpected attack vectors. This flaw demonstrates the importance of thorough testing of security controls in complex network environments, particularly when multiple layers of network services interact with each other. Organizations should implement comprehensive network monitoring solutions to detect potential exploitation attempts, while also reviewing their NAT configurations to ensure they do not inadvertently create security vulnerabilities. The vulnerability serves as a reminder of the critical need for maintaining up-to-date security patches and the potential consequences of failing to address known security flaws in operating system components that handle critical network functions.