CVE-2002-2336 in Norton Personal Firewall
Summary
by MITRE
Norton Personal Firewall 2002 4.0, when configured to automatically block attacks, allows remote attackers to block IP addresses and cause a denial of service via spoofed packets.
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Analysis
by VulDB Data Team • 05/06/2025
The vulnerability described in CVE-2002-2336 represents a critical flaw in Norton Personal Firewall 2002 version 4.0 that enables remote attackers to manipulate the firewall's automatic blocking mechanism. This issue stems from the firewall's improper handling of spoofed network packets, specifically those that appear to originate from legitimate sources but are actually fabricated by malicious actors. The vulnerability exists within the firewall's packet validation and filtering logic, where it fails to properly authenticate or verify the legitimacy of incoming packets before applying blocking actions. When configured to automatically block attacks, the firewall's behavior becomes exploitable as attackers can craft malicious packets that mimic legitimate traffic patterns, causing the firewall to incorrectly identify these spoofed packets as threats and subsequently block the IP addresses from which they originate.
The technical implementation of this vulnerability aligns with CWE-284, which addresses improper access control mechanisms, and CWE-310, which covers cryptographic weaknesses in security systems. The flaw operates at the network protocol level where the firewall's automatic blocking feature lacks sufficient validation of packet source authenticity. Attackers can exploit this by sending spoofed packets that appear to come from targeted IP addresses, triggering the firewall's automatic blocking mechanism to block those addresses. This creates a cascading effect where legitimate users or services associated with the blocked IP addresses become inaccessible, effectively rendering them unavailable to their intended users. The vulnerability demonstrates a fundamental weakness in the firewall's trust model, where it accepts the source IP address information in packets without sufficient verification, leading to a scenario where an attacker can manipulate the firewall's access control decisions.
The operational impact of this vulnerability extends beyond simple network disruption to encompass broader security implications that affect both availability and integrity of network services. When exploited, the vulnerability allows attackers to cause denial of service against specific IP addresses or ranges, potentially targeting critical infrastructure or legitimate users within the network. The attack vector is particularly concerning because it requires minimal privileges to execute and can be automated, making it a potent tool for network disruption. The firewall's automatic blocking feature, designed to protect users from malicious traffic, becomes a mechanism for enabling the very attacks it was meant to prevent. This creates a paradoxical security weakness where the defensive measures of the system become the primary vector for exploitation, undermining the fundamental security posture of the protected network.
Mitigation strategies for CVE-2002-2336 should focus on implementing more robust packet validation mechanisms and disabling or carefully configuring the automatic blocking feature in vulnerable firewall implementations. Organizations should consider disabling the automatic blocking functionality until a patched version is available, as this feature directly enables the exploitation. Network administrators should also implement additional monitoring and logging to detect anomalous blocking patterns that may indicate exploitation attempts. The vulnerability highlights the importance of proper input validation and authentication mechanisms in security systems, as outlined in the ATT&CK framework's defense evasion techniques. Implementing rate limiting on blocking operations and requiring explicit confirmation for blocking actions can help prevent unauthorized manipulation of access control decisions. Additionally, network segmentation and intrusion detection systems should be deployed to monitor for suspicious packet patterns that may indicate spoofing attempts, providing an additional layer of protection against this class of vulnerability.