CVE-2002-2254 in Linux
Summary
by MITRE
The experimental IP packet queuing feature in Netfilter / IPTables in Linux kernel 2.4 up to 2.4.19 and 2.5 up to 2.5.31, when a privileged process exits and network traffic is not being queued, may allow a later process with the same Process ID (PID) to access certain network traffic that would otherwise be restricted.
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Analysis
by VulDB Data Team • 06/12/2018
The vulnerability described in CVE-2002-2254 resides within the Netfilter framework's experimental IP packet queuing functionality in Linux kernels version 2.4 through 2.4.19 and 2.5 through 2.5.31. This issue stems from a fundamental flaw in how the kernel manages network packet queuing state when privileged processes terminate, creating a potential security bypass mechanism that affects the integrity of network access controls. The vulnerability specifically targets the interaction between process lifecycle management and network packet queuing mechanisms, where the kernel fails to properly clear or invalidate queuing state information associated with terminated privileged processes.
The technical implementation flaw occurs when a privileged process that was previously engaged in network packet queuing operations terminates and exits the system. Under normal circumstances, the kernel should properly clean up all associated network queuing contexts and permissions. However, this vulnerability allows a subsequent process to assume the same process identifier as the terminated privileged process, thereby inheriting the previous process's queuing context and potentially gaining unauthorized access to network traffic that should have been restricted. This represents a classic case of improper state management and process identifier reuse in security-sensitive contexts, where the kernel's resource cleanup mechanism fails to properly isolate network access permissions.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally undermines the network access control mechanisms that rely on process-based queuing permissions. Attackers can exploit this weakness by creating a scenario where they can manipulate process lifecycle events to gain access to network traffic that would normally be restricted to specific privileged processes. This affects systems that depend on iptables rules and Netfilter packet queuing for network security policies, potentially allowing unauthorized access to sensitive network data, interception of communications, or manipulation of network flows that should remain protected from non-privileged access.
Mitigation strategies for this vulnerability require careful consideration of both immediate system hardening and long-term architectural improvements. System administrators should ensure that affected kernel versions are patched or upgraded to versions that address this specific queuing state management issue. The recommended approach involves implementing proper process identifier reuse controls and ensuring that network queuing contexts are properly cleared when processes terminate. Organizations should also consider implementing additional monitoring for process lifecycle events and network queuing operations to detect anomalous behavior that might indicate exploitation attempts. This vulnerability aligns with CWE-362, which addresses race conditions in concurrent access to shared resources, and maps to ATT&CK technique T1068, which involves local privilege escalation through exploitation of system vulnerabilities. The fix typically involves ensuring proper cleanup of queuing state information during process termination and implementing stricter isolation mechanisms between different process contexts within the Netfilter subsystem.