CVE-2013-1100 in IOS
Summary
by MITRE
The HTTP server in Cisco IOS on Catalyst switches does not properly handle TCP socket events, which allows remote attackers to cause a denial of service (device crash) via crafted packets on TCP port (1) 80 or (2) 443, aka Bug ID CSCuc53853.
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Analysis
by VulDB Data Team • 04/24/2017
The vulnerability identified as CVE-2013-1100 represents a critical denial of service flaw within Cisco IOS operating systems running on Catalyst switches. This weakness specifically affects the HTTP server implementation that handles incoming network connections on standard web ports 80 and 443, making it particularly dangerous for network infrastructure devices that may be exposed to external traffic. The vulnerability stems from improper handling of TCP socket events, which constitutes a fundamental failure in the network protocol stack's connection management mechanisms.
The technical flaw manifests when remote attackers send specially crafted TCP packets to the affected switch's HTTP server listening on ports 80 or 443. These malformed packets trigger a condition where the TCP socket state machine fails to properly process connection events, leading to an uncontrolled crash of the device's operating system. The vulnerability is classified as a buffer overflow or memory corruption issue within the TCP processing code, which can be categorized under CWE-121 in the Common Weakness Enumeration taxonomy. This type of flaw typically occurs when the system does not properly validate or sanitize incoming connection data before processing it within the socket handling routines.
The operational impact of this vulnerability extends beyond simple service disruption, as it can result in complete device unavailability and network downtime. Catalyst switches are critical network infrastructure components that often serve as core routing points, making their compromise particularly damaging to enterprise networks. When exploited, the vulnerability can cause cascading failures throughout the network as dependent systems lose connectivity to the affected switch. This type of attack aligns with ATT&CK technique T1499.004, which describes network denial of service attacks that target infrastructure devices. The vulnerability affects multiple Cisco IOS versions and is particularly concerning because it can be exploited remotely without requiring authentication, making it an attractive target for automated scanning and exploitation.
Mitigation strategies for CVE-2013-1100 focus on immediate network segmentation and access control measures. Organizations should implement firewall rules to block external access to TCP ports 80 and 443 on affected switches, particularly when these services are not required for legitimate network operations. Cisco released specific patches and workarounds for this vulnerability, including IOS software updates that address the TCP socket handling logic. Network administrators should also consider disabling HTTP server functionality on switches when it is not essential for operations. The vulnerability demonstrates the importance of proper input validation and robust error handling in network protocol implementations, as highlighted in the NIST Cybersecurity Framework's configuration management practices. Regular vulnerability assessments and network monitoring should be implemented to detect potential exploitation attempts and ensure that all network infrastructure components remain up to date with security patches.