CVE-2022-22278 in SonicOS
Summary
by MITRE • 04/27/2022
A vulnerability in SonicOS CFS (Content filtering service) returns a large 403 forbidden HTTP response message to the source address when users try to access prohibited resource this allows an attacker to cause HTTP Denial of Service (DoS) attack
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Analysis
by VulDB Data Team • 04/30/2022
The vulnerability identified as CVE-2022-22278 affects SonicOS CFS (Content Filtering Service) and represents a significant security flaw that can be exploited to execute HTTP Denial of Service attacks. This vulnerability specifically manifests when users attempt to access prohibited resources through the content filtering service, triggering an unintended behavior that exposes the system to potential abuse. The flaw resides in the service's response mechanism, where it generates an oversized 403 forbidden HTTP response message that is sent back to the originating client address. This excessive response size creates an opportunity for attackers to exploit the service's handling of forbidden requests and leverage the oversized response to consume network bandwidth and system resources.
The technical implementation of this vulnerability stems from improper handling of HTTP response generation within the SonicOS CFS component. When a user attempts to access content that is blocked by the content filtering rules, the system does not properly limit the size of the response message returned to the client. This results in the generation of a disproportionately large 403 forbidden response that can contain extensive error details, headers, or even embedded content that exceeds normal response size limits. The oversized response can be particularly problematic when multiple concurrent requests are made to the service, as each request generates a large response that can overwhelm network connections and consume significant processing power.
From an operational perspective, this vulnerability presents a substantial risk to organizations relying on SonicOS for content filtering and network security. The DoS attack vector allows adversaries to consume network bandwidth and system resources through relatively simple means, requiring minimal technical expertise to execute. Attackers can leverage this flaw by repeatedly requesting access to prohibited resources, causing the system to generate and transmit large response messages that can saturate network connections and degrade service availability. The impact extends beyond simple service disruption, as the excessive response sizes can cause cascading effects throughout the network infrastructure, potentially affecting other services and applications that depend on the same network resources.
The vulnerability aligns with CWE-400, which addresses "Uncontrolled Resource Consumption" and specifically covers issues where applications fail to properly limit resource usage. This weakness creates a direct pathway for attackers to consume excessive system resources through legitimate service operations. From an ATT&CK framework perspective, this vulnerability maps to techniques involving resource exhaustion and denial of service, particularly targeting network services through HTTP protocol manipulation. The attack chain typically involves initial reconnaissance to identify vulnerable SonicOS instances, followed by exploitation of the oversized response behavior to consume network bandwidth and processing capacity. Organizations should consider implementing network-level protections such as rate limiting and connection throttling to mitigate the impact of such attacks.
Mitigation strategies for CVE-2022-22278 should focus on both immediate defensive measures and long-term architectural improvements. Organizations should prioritize applying vendor patches and updates as soon as they become available, as these typically address the root cause by implementing proper response size limitations and resource management controls. Network administrators should implement rate limiting policies at the perimeter to restrict the number of requests that can be processed from any single source address within a given time period. Additionally, monitoring systems should be configured to detect unusual patterns of 403 response generation and alert security teams to potential exploitation attempts. The implementation of proper input validation and response size controls within the content filtering service can prevent the generation of oversized responses that contribute to the DoS vulnerability. Organizations should also consider implementing intrusion detection systems that can identify and block malicious request patterns targeting this specific vulnerability.