CVE-2022-20697 in IOS
Summary
by MITRE • 04/15/2022
A vulnerability in the web services interface of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition. This vulnerability is due to improper resource management in the HTTP server code. An attacker could exploit this vulnerability by sending a large number of HTTP requests to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
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Analysis
by VulDB Data Team • 04/20/2022
This vulnerability resides within the web services interface of Cisco IOS and IOS XE software implementations, representing a significant security concern for network infrastructure devices. The flaw manifests in the HTTP server component's handling of resource allocation and management, creating an exploitable condition that can be triggered remotely by authenticated users. The vulnerability specifically targets the improper resource management practices within the web services framework, where the system fails to adequately handle concurrent or excessive HTTP request processing. This weakness allows an attacker with valid credentials to manipulate the device's resource consumption patterns in a manner that ultimately leads to system instability.
The technical exploitation mechanism leverages the HTTP server's inability to properly manage resource allocation when processing multiple simultaneous requests. When an authenticated attacker sends a large volume of HTTP requests to the affected device, the system's resource management routines become overwhelmed, leading to a cascade of failures in the web services component. This improper handling of resource consumption causes the device to enter a state where it must restart its web services or entire system to recover from the resource exhaustion condition. The vulnerability demonstrates a classic denial of service pattern where legitimate service availability is compromised through resource manipulation rather than direct system exploitation.
The operational impact of this vulnerability extends beyond simple service disruption, as it can potentially cause complete device unavailability and require manual intervention for recovery. Network administrators may experience extended downtime while the affected device undergoes automatic restart procedures or requires manual rebooting to restore normal operations. This type of vulnerability particularly affects enterprise networks where web-based management interfaces are commonly used for device configuration and monitoring, potentially disrupting critical network operations and requiring immediate response protocols. The authentication requirement limits the attack surface compared to unauthenticated vulnerabilities, but still presents a significant risk to networks where privileged accounts may be compromised.
Mitigation strategies should focus on implementing rate limiting controls and resource monitoring for HTTP server components within the affected Cisco devices. Network security teams should deploy access control measures that restrict the number of concurrent HTTP connections and implement automated monitoring to detect unusual request patterns that may indicate exploitation attempts. The vulnerability aligns with CWE-400 which categorizes resource exhaustion as a fundamental weakness in software design, and can be mapped to ATT&CK technique T1499 which covers network denial of service attacks. Cisco has released patches and updates to address this specific resource management flaw, and organizations should prioritize applying these security updates to prevent exploitation. Additionally, implementing network segmentation and limiting web service access to trusted administrative networks can reduce the attack surface and provide additional defense-in-depth measures against this particular vulnerability.