CVE-2002-2397 in Sygate Personal Firewall
Summary
by MITRE
Sygate personal firewall 5.0 could allow remote attackers to bypass firewall filters via spoofed (1) source IP address of 127.0.0.1 or (2) network address of 127.0.0.0.
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Analysis
by VulDB Data Team • 07/14/2024
The vulnerability identified as CVE-2002-2397 affects Sygate Personal Firewall version 5.0 and represents a significant security flaw in network traffic filtering mechanisms. This weakness stems from the firewall's improper handling of loopback address traffic, specifically when packets are spoofed with source IP addresses or network addresses that belong to the loopback range. The vulnerability exploits a fundamental misunderstanding of how loopback addresses should be treated within network security contexts, creating a pathway for malicious actors to circumvent the firewall's protective measures.
The technical implementation of this vulnerability relies on the attacker's ability to craft network packets with spoofed loopback addresses, specifically targeting the 127.0.0.1 and 127.0.0.0 network ranges. These addresses are reserved for loopback functionality within TCP/IP networks and should typically be restricted from external traffic, as they represent internal system communication channels. When the Sygate firewall processes packets with these spoofed addresses, it fails to properly validate or filter them according to standard security protocols, allowing potentially malicious traffic to pass through the firewall's inspection mechanisms.
This vulnerability directly impacts the operational security posture of systems running the affected firewall version, as it creates a persistent bypass mechanism that attackers can exploit to gain unauthorized access to protected network resources. The implications extend beyond simple traffic filtering, as successful exploitation could enable attackers to perform reconnaissance, establish covert communication channels, or launch more sophisticated attacks against the targeted system. The flaw particularly affects systems where loopback addresses are not properly segregated from external network traffic, creating a vector for privilege escalation and lateral movement within the network infrastructure.
The vulnerability maps to CWE-284, which addresses improper access control, and aligns with ATT&CK techniques related to privilege escalation and defense evasion. Organizations implementing this firewall version face significant risk exposure, as the bypass mechanism operates at the network layer without requiring elevated privileges or complex attack vectors. The security impact is compounded by the fact that loopback addresses are commonly used for internal system services and should be treated with the same security scrutiny as external traffic, yet the firewall fails to maintain this critical distinction.
Mitigation strategies for CVE-2002-2397 require immediate attention through firmware updates and configuration modifications. The primary solution involves applying the vendor-provided security patches that address the loopback address handling logic within the firewall's packet inspection engine. Network administrators should also implement additional monitoring measures to detect anomalous traffic patterns involving loopback addresses, particularly when these addresses appear in external traffic contexts. Configuration adjustments may include explicitly blocking loopback addresses from external interfaces and implementing stricter validation rules for packet source addresses. Organizations should conduct comprehensive security assessments to identify systems running the vulnerable software version and prioritize remediation efforts based on risk exposure and network architecture dependencies.