CVE-2020-24554 in Liferay Portal
Summary
by MITRE
The redirect module in Liferay Portal before 7.3.3 does not limit the number of URLs resulting in a 404 error that is recorded, which allows remote attackers to perform a denial of service attack by making repeated requests for pages that do not exist.
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Analysis
by VulDB Data Team • 11/12/2020
The vulnerability identified as CVE-2020-24554 resides within the redirect module of Liferay Portal versions prior to 7.3.3, representing a critical denial of service weakness that can be exploited by remote attackers to disrupt system availability. This flaw manifests when the portal fails to implement proper rate limiting or URL tracking restrictions on the number of 404 error responses that are recorded within the redirect module. The absence of such limitations creates an exploitable condition where malicious actors can systematically generate a large volume of requests for non-existent pages, causing the system to accumulate an excessive number of recorded 404 URLs without any form of mitigation or cleanup mechanism.
The technical implementation of this vulnerability stems from inadequate input validation and resource management within the redirect handling component of Liferay Portal. When users or attackers make requests for URLs that do not exist within the portal, the system logs these 404 errors in the redirect module's internal storage. Without bounds on the number of entries that can be recorded, each failed request contributes to an ever-growing dataset that consumes system resources including memory allocation, disk space, and processing power required to maintain and query the redirect table. This unbounded growth in recorded URLs directly impacts the portal's performance and can eventually lead to complete system unresponsiveness or crash conditions.
From an operational perspective, this vulnerability presents a significant risk to organizations relying on Liferay Portal for their web content management and enterprise portal services. Attackers can leverage this flaw to launch sustained denial of service attacks that consume system resources without requiring authentication or specialized privileges. The impact extends beyond simple service disruption as the accumulation of 404 entries can cause database performance degradation, increased memory consumption, and potential application instability that affects legitimate user access to the portal. The vulnerability is particularly concerning because it can be exploited using simple HTTP requests, making it accessible to attackers with minimal technical expertise and no specific attack vectors required.
The mitigation strategy for CVE-2020-24554 involves upgrading to Liferay Portal version 7.3.3 or later, which includes the necessary fixes to implement proper rate limiting and URL tracking restrictions within the redirect module. Organizations should also implement additional defensive measures such as configuring web application firewalls to monitor and limit excessive requests to non-existent URLs, implementing proper logging and monitoring to detect unusual patterns of 404 errors, and establishing automated cleanup processes for redirect entries. This vulnerability aligns with CWE-770, which addresses the allocation of resources without proper limits or monitoring, and maps to ATT&CK technique T1499.004 for denial of service through resource exhaustion attacks. System administrators should also consider implementing request throttling mechanisms and access controls to prevent abuse of the redirect functionality while maintaining legitimate portal operations and user experience.