CVE-2018-0282 in IOS
Summary
by MITRE
A vulnerability in the TCP socket code of Cisco IOS and IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to a state condition between the socket state and the transmission control block (TCB) state. While this vulnerability potentially affects all TCP applications, the only affected application observed so far is the HTTP server. An attacker could exploit this vulnerability by sending specific HTTP requests at a sustained rate to a reachable IP address of the affected software. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition on an affected device.
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Analysis
by VulDB Data Team • 06/23/2023
The vulnerability described in CVE-2018-0282 represents a critical state management flaw within the Transmission Control Protocol implementation of Cisco IOS and IOS XE software platforms. This issue stems from a fundamental mismatch between the socket state and the Transmission Control Block state, creating a condition where the TCP stack fails to properly handle concurrent connection states. The vulnerability specifically impacts the TCP socket code, which serves as the foundational layer for all TCP-based network communications including HTTP services. The flaw manifests when the system encounters certain combinations of socket state transitions and TCB state updates that are not properly validated or handled within the protocol implementation.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the availability of critical network infrastructure. While the vulnerability affects all TCP applications running on the affected platforms, the primary observed exploitation vector involves the HTTP server application, making it particularly concerning for web-facing devices. Attackers can exploit this weakness by crafting and sending sustained streams of specific HTTP requests to targeted IP addresses, leveraging the inherent state condition to trigger device reloads. This exploitation method aligns with common denial-of-service attack patterns and demonstrates how protocol-level implementation flaws can be weaponized to create persistent service disruptions.
The technical nature of this vulnerability places it within the scope of CWE-121, which addresses buffer overflow conditions, and CWE-362, which covers concurrent execution use of lock objects. The state synchronization issue between socket and TCB components creates a race condition scenario where improper state transitions lead to system instability. From an attack framework perspective, this vulnerability maps to the MITRE ATT&CK technique T1499.004 for Network Denial of Service, and represents a classic example of how operating system kernel flaws can be leveraged to create persistent availability issues. The sustained rate of HTTP requests required for exploitation suggests that this vulnerability could be difficult to detect in network monitoring systems, as it might appear as legitimate traffic patterns before triggering the underlying state condition.
Cisco's vulnerability assessment identified that the affected software versions include multiple releases of IOS and IOS XE, making this a widespread concern across enterprise network infrastructure. The remediation approach typically involves applying the appropriate software patches and updates released by Cisco, which address the socket state handling logic and ensure proper synchronization between socket and TCB states. Network administrators should also consider implementing traffic filtering measures to limit the rate of HTTP requests to affected devices, providing additional defense-in-depth protection. The vulnerability highlights the critical importance of proper state management in network protocol implementations and serves as a reminder of how seemingly minor implementation details can create significant security risks in network infrastructure software.