CVE-2000-0700 in IOS
Summary
by MITRE
Cisco Gigabit Switch Routers (GSR) with Fast Ethernet / Gigabit Ethernet cards, from IOS versions 11.2(15)GS1A up to 11.2(19)GS0.2 and some versions of 12.0, do not properly handle line card failures, which allows remote attackers to bypass ACLs or force the interface to stop forwarding packets.
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Analysis
by VulDB Data Team • 10/13/2025
The vulnerability identified as CVE-2000-0700 affects Cisco Gigabit Switch Routers operating with Fast Ethernet and Gigabit Ethernet cards running specific IOS versions ranging from 11.2(15)GS1A through 11.2(19)GS0 and certain releases of IOS 12.0. This weakness represents a critical flaw in the router's handling of hardware component failures, specifically line card malfunctions that occur during normal network operations. The vulnerability stems from inadequate error handling mechanisms within the IOS software that govern how the router responds when line card components fail unexpectedly.
The technical implementation of this vulnerability involves the router's failure to properly manage line card failure events, which creates a condition where remote attackers can exploit the system's response to these hardware failures. When line cards experience faults, the affected router does not properly maintain access control list enforcement or packet forwarding functionality, allowing unauthorized network access and potential traffic disruption. This flaw operates at the network infrastructure level where the router's software fails to maintain proper security boundaries when hardware components become non-functional.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it enables attackers to bypass existing access control mechanisms that are fundamental to network security. The ability to force interfaces to stop forwarding packets creates a potential for network disruption while simultaneously allowing unauthorized access to network resources that should be protected by access control lists. This dual nature of the vulnerability makes it particularly dangerous in enterprise environments where network security is paramount and access controls are essential for protecting sensitive data and systems.
This vulnerability aligns with CWE-284, which addresses improper access control mechanisms, and relates to ATT&CK technique T1071.004 for application layer protocol: DNS, as attackers could potentially exploit the network disruption capabilities to interfere with critical network services. The flaw demonstrates a failure in the router's fault tolerance design and proper error handling procedures, creating a security boundary that can be circumvented through manipulation of hardware failure conditions. Organizations should implement immediate mitigations including IOS version upgrades to patched releases, enhanced monitoring of line card status, and implementation of additional network segmentation controls to prevent exploitation of this vulnerability.