CVE-2003-0100 in IOS
Summary
by MITRE
Buffer overflow in Cisco IOS 11.2.x to 12.0.x allows remote attackers to cause a denial of service and possibly execute commands via a large number of OSPF neighbor announcements.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 09/11/2024
The vulnerability described in CVE-2003-0100 represents a critical buffer overflow flaw within Cisco IOS software versions 11.2.x through 12.0.x that specifically affects the Open Shortest Path First routing protocol implementation. This issue stems from inadequate input validation mechanisms within the OSPF neighbor announcement processing code, where the system fails to properly bounds-check the size of incoming neighbor advertisements. The flaw exists in the routing protocol handler that processes OSPF packets, particularly when multiple neighbor announcements are received in rapid succession, creating a condition where memory allocated for neighbor data structures becomes overflowed. According to CWE-121, this vulnerability manifests as a classic stack-based buffer overflow, where attacker-controlled data exceeds the allocated buffer space, potentially corrupting adjacent memory locations including return addresses and control data.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enable remote code execution, making it a severe threat to network infrastructure integrity. When an attacker sends a large number of malformed OSPF neighbor announcements to a vulnerable Cisco IOS device, the buffer overflow can cause the routing process to crash and restart, resulting in temporary network disruption and potential routing table corruption. However, the more concerning aspect is that under specific conditions, the overflow may allow attackers to overwrite critical memory locations with malicious code, enabling arbitrary command execution on the affected device. This vulnerability directly impacts the availability and integrity of network services, as routing protocols form the backbone of network communication and any compromise can lead to widespread service disruption.
Network attackers can exploit this vulnerability by crafting specially designed OSPF packets containing oversized neighbor advertisements that trigger the buffer overflow condition. The attack requires minimal privileges and can be executed remotely, making it particularly dangerous for network infrastructure devices that are often accessible from untrusted networks. The vulnerability affects Cisco IOS versions that were widely deployed in enterprise and service provider networks, amplifying the potential impact across multiple organizations. According to ATT&CK framework category T1203, this represents a remote code execution technique that leverages protocol implementation flaws to gain unauthorized access to network devices. The flaw is particularly concerning because it operates at the network protocol level, where attackers can remain undetected while compromising core routing functionality.
Cisco addressed this vulnerability through firmware updates that included enhanced input validation and proper bounds checking for OSPF neighbor announcement processing. Organizations should implement immediate mitigations including access control lists to filter OSPF traffic, disabling OSPF on untrusted interfaces, and applying the latest IOS patches. Network segmentation and monitoring solutions should be deployed to detect abnormal OSPF traffic patterns that may indicate exploitation attempts. The vulnerability also highlights the importance of proper input validation in network protocol implementations, as emphasized by CWE-707, which recommends defensive programming practices including buffer size verification and proper memory management techniques. Regular security assessments and vulnerability scanning should be conducted to identify other potential buffer overflow conditions in network infrastructure components, ensuring comprehensive protection against similar threats.