CVE-2019-8909 in WTCMS
Summary
by MITRE
An issue was discovered in WTCMS 1.0. It allows remote attackers to cause a denial of service (resource consumption) via crafted dimensions for the verification code image.
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Analysis
by VulDB Data Team • 07/11/2023
The vulnerability identified as CVE-2019-8909 affects WTCMS version 1.0 and represents a significant denial of service weakness that can be exploited remotely by attackers. This issue specifically targets the verification code image generation functionality within the content management system, creating a scenario where malicious actors can consume excessive system resources through carefully crafted input parameters. The vulnerability stems from inadequate validation and sanitization of image dimension parameters used in the captcha generation process, allowing attackers to submit malformed or excessively large dimension values that cause the system to allocate excessive memory or processing power.
The technical flaw manifests when the CMS processes verification code image requests with malformed dimension parameters that trigger resource exhaustion conditions. Attackers can submit extremely large width and height values or manipulate the image generation algorithm to force the system into consuming disproportionate computational resources. This type of vulnerability falls under CWE-400, which specifically addresses uncontrolled resource consumption, and represents a classic example of a resource exhaustion attack that can effectively disable the targeted service. The vulnerability is particularly dangerous because it can be exploited without requiring authentication or prior access to the system, making it a low-hanging fruit for attackers seeking to disrupt service availability.
From an operational impact perspective, this vulnerability can lead to complete service disruption for legitimate users of the WTCMS platform. When exploited, the denial of service condition can cause the web server to become unresponsive or crash entirely, preventing users from accessing the website or completing authentication processes. The resource consumption can escalate to the point where the entire server becomes unavailable, affecting not just the verification code functionality but potentially other system components that rely on the same underlying resources. This vulnerability directly impacts the availability component of the CIA triad and can be leveraged as part of broader attack campaigns targeting the overall system stability and user experience.
Mitigation strategies for CVE-2019-8909 should focus on implementing robust input validation and parameter sanitization for all image dimension parameters used in the verification code generation process. The system should enforce strict limits on maximum image dimensions and implement proper bounds checking to prevent excessive resource allocation. Security controls should include implementing rate limiting mechanisms to prevent abuse of the verification code functionality and establishing monitoring systems to detect unusual resource consumption patterns. Organizations should also consider implementing proper error handling and graceful degradation mechanisms to ensure that even if the vulnerability is exploited, the overall system remains functional. From an ATT&CK framework perspective, this vulnerability maps to T1499.004, which covers network denial of service, and represents a critical weakness that requires immediate attention to prevent potential exploitation by threat actors seeking to disrupt service availability. The vulnerability also highlights the importance of input validation as a fundamental security control that should be implemented across all web applications to prevent similar resource exhaustion attacks.