CVE-2003-0305 in IOS
Summary
by MITRE
The Service Assurance Agent (SAA) in Cisco IOS 12.0 through 12.2, aka Response Time Reporter (RTR), allows remote attackers to cause a denial of service (crash) via malformed RTR packets to port 1967.
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Analysis
by VulDB Data Team • 08/20/2025
The vulnerability identified as CVE-2003-0305 affects Cisco IOS versions 12.0 through 12.2 and specifically targets the Service Assurance Agent also known as Response Time Reporter which operates on port 1967. This critical flaw represents a remote denial of service vulnerability that can be exploited by unauthorized attackers to crash network devices running affected Cisco IOS versions. The Service Assurance Agent is designed to monitor network performance and provide response time measurements for network services, making it a crucial component for network management and assurance. However, the implementation contains a buffer overflow or input validation flaw that manifests when processing malformed RTR packets, causing the system to become unstable and eventually crash.
The technical exploitation of this vulnerability occurs through the manipulation of RTR protocol packets sent to the designated port 1967, which is the default port used by the Response Time Reporter service. Attackers can craft specially malformed packets that trigger memory corruption or stack overflow conditions within the SAA component of Cisco IOS. This type of vulnerability falls under CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of insufficient input validation in network protocols. The flaw demonstrates poor error handling within the packet processing routines, where the system fails to properly validate packet headers, lengths, or content before attempting to process them, leading to unpredictable behavior and system instability.
The operational impact of this vulnerability extends beyond simple service disruption, as it can affect network availability and reliability for organizations relying on Cisco networking equipment. When exploited successfully, the vulnerability causes the targeted device to crash and restart, potentially resulting in network outages or service degradation that affects multiple users and applications. Network administrators may experience difficulties in maintaining consistent network performance monitoring since the Response Time Reporter service, which is essential for tracking network quality metrics, becomes unavailable. This vulnerability particularly affects enterprise networks where Cisco routers and switches serve as critical infrastructure components for maintaining connectivity and service assurance.
Mitigation strategies for CVE-2003-0305 should include immediate implementation of network segmentation to restrict access to port 1967 from untrusted networks and implementing access control lists to filter malicious traffic. Cisco recommends applying the appropriate software patches and updates to upgrade affected IOS versions to those containing fixes for the RTR processing vulnerabilities. Network administrators should also consider disabling the Response Time Reporter service entirely if it is not required for their network operations, as this eliminates the attack surface. Additionally, implementing network monitoring solutions that can detect anomalous packet patterns on port 1967 helps in early identification of potential exploitation attempts. The vulnerability aligns with ATT&CK technique T1499.004 which covers network denial of service attacks, and represents a common vector for network infrastructure compromise through service disruption attacks. Organizations should also implement proper network hygiene practices including regular vulnerability assessments and patch management processes to prevent similar issues from occurring in other network components.