CVE-2003-1003 in PIX
Summary
by MITRE
Cisco PIX firewall 5.x.x, and 6.3.1 and earlier, allows remote attackers to cause a denial of service (crash and reload) via an SNMPv3 message when snmp-server is set.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 06/29/2021
The vulnerability identified as CVE-2003-1003 represents a critical denial of service flaw affecting Cisco PIX firewalls running version 5.x.x and 6.3.1 or earlier. This weakness specifically manifests when the SNMPv3 protocol is enabled through the snmp-server configuration command, creating a condition where remote attackers can exploit the system's handling of SNMP messages to trigger a complete firewall crash and subsequent reload. The vulnerability demonstrates the inherent risks associated with network management protocols when improperly implemented or validated within security infrastructure devices.
The technical flaw resides in the insufficient input validation and error handling mechanisms within the SNMPv3 processing code of the affected Cisco PIX firewall versions. When an SNMPv3 message is received and processed by the firewall's management subsystem, the system fails to properly validate the message structure or handle malformed packets, leading to memory corruption or unexpected state transitions that ultimately cause the device to crash. This issue falls under the CWE category of insufficient input validation, specifically CWE-20, which addresses weaknesses in the validation of input data that can lead to various security vulnerabilities including denial of service conditions.
The operational impact of this vulnerability extends beyond simple service disruption as it represents a significant threat to network availability and business continuity. Remote attackers can exploit this weakness without requiring authentication credentials, making it particularly dangerous as it allows unauthorized parties to compromise network security infrastructure. The automatic reload process triggered by the crash creates additional operational challenges including potential loss of network connectivity during the recovery period and possible disruption of network monitoring capabilities that rely on SNMP for device status reporting. This vulnerability directly impacts the availability component of the CIA triad and can be classified under ATT&CK technique T1499.004 for network denial of service attacks.
Mitigation strategies for this vulnerability require immediate implementation of security patches provided by Cisco, specifically targeting the affected PIX firewall versions. Organizations should disable SNMPv3 functionality on affected devices when not strictly necessary, and implement network segmentation to limit exposure to potentially malicious actors. The recommended approach includes upgrading to patched versions of the PIX firewall software, configuring access controls to limit SNMP access to trusted management stations, and implementing network monitoring to detect anomalous SNMP traffic patterns that may indicate exploitation attempts. Additionally, organizations should establish incident response procedures to address potential service disruptions and ensure proper backup and recovery mechanisms are in place to minimize business impact during remediation activities.