CVE-2002-0782 in BorderManager
Summary
by MITRE
Novell BorderManager 3.5 with PAT (Port-Address Translate) enabled allows remote attackers to cause a denial of service by filling the connection table with a large number of connection requests to hosts that do not have a specific route, which may be forwarded to the public interface.
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Analysis
by VulDB Data Team • 06/24/2024
The vulnerability identified as CVE-2002-0782 affects Novell BorderManager 3.5 when Port-Address Translation (PAT) functionality is enabled. This represents a critical denial of service weakness that exploits the router's connection handling mechanisms. The flaw resides in how the system manages connection table entries when processing requests directed toward destinations without specific routing paths. When attackers flood the system with connection attempts to unreachable hosts, the BorderManager device becomes overwhelmed with connection table entries that cannot be properly resolved, leading to resource exhaustion and service disruption. This vulnerability specifically targets the network address translation process where the system attempts to forward traffic to public interfaces without proper routing configuration.
The technical implementation of this vulnerability demonstrates a classic resource exhaustion attack pattern where the attacker leverages the PAT feature's connection tracking mechanism. When PAT is enabled, the system maintains a connection table to track translation mappings between internal and external addresses. The flaw occurs because the device does not adequately manage or limit the creation of connection entries for non-routable destinations. Attackers can exploit this by sending a large volume of connection requests to IP addresses that lack specific routing entries, causing the connection table to fill rapidly with invalid entries. This creates a cascading effect where legitimate connections cannot be established due to the exhaustion of available table slots, effectively rendering the network service unavailable to authorized users.
The operational impact of CVE-2002-0782 extends beyond simple service disruption to potentially compromise network availability and business continuity. Organizations relying on Novell BorderManager for network security and traffic management face significant risks when this vulnerability is exploited. The attack can be executed remotely without requiring authentication, making it particularly dangerous as any network entity can potentially trigger the denial of service condition. The vulnerability affects the core functionality of the BorderManager's PAT implementation, which is fundamental to network address translation and security policy enforcement. This weakness can be classified under CWE-400 as "Uncontrolled Resource Consumption" and aligns with ATT&CK technique T1499.1 for "Endpoint Denial of Service" where attackers target resource exhaustion to make systems unavailable.
Mitigation strategies for this vulnerability require immediate implementation of connection rate limiting and connection table size restrictions within the BorderManager configuration. Network administrators should configure maximum connection limits and implement proper access controls to prevent unauthorized exploitation. The most effective approach involves disabling PAT functionality when it is not required or implementing strict filtering rules that prevent connection requests to non-routable destinations. Additionally, monitoring systems should be deployed to detect unusual patterns in connection table usage, providing early warning of potential exploitation attempts. Organizations should also consider implementing network segmentation to limit the exposure of BorderManager devices to external threats. The vulnerability highlights the importance of proper resource management and connection tracking in network security appliances, emphasizing that even legitimate network functions can become attack vectors when not properly constrained.