CVE-2017-18353 in Rendertron
Summary
by MITRE
Rendertron 1.0.0 includes an _ah/stop route to shutdown the Chrome instance responsible for serving render requests to all users. Visiting this route with a GET request allows any unauthorized remote attacker to disable the core service of the application.
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Analysis
by VulDB Data Team • 06/19/2023
The vulnerability identified as CVE-2017-18353 resides within Rendertron version 1.0.0, a service designed to render web pages for server-side rendering purposes. This application operates by utilizing a Chrome instance to process and generate rendered content for web applications, making it a critical component in web development environments where server-side rendering is required. The flaw manifests in the implementation of an administrative endpoint that was intended for legitimate service management purposes but lacks proper authentication mechanisms. The _ah/stop route serves as a shutdown mechanism for the Chrome instance that handles all user render requests, effectively creating a single point of failure that can be exploited by malicious actors.
The technical implementation of this vulnerability stems from the absence of access controls on the shutdown endpoint within the Rendertron application. When an attacker sends a simple GET request to the _ah/stop route, the application processes this request without verifying the requester's authorization status. This design flaw allows any remote user to execute a service disruption attack that terminates the Chrome instance responsible for rendering web content. The vulnerability operates at the application layer and represents a classic case of insecure direct object reference, where administrative functions are exposed without proper authentication. According to CWE-284, this weakness falls under inadequate access control, specifically the failure to restrict access to administrative functions. The flaw also aligns with ATT&CK technique T1499.004, which describes the exploitation of application vulnerabilities to disrupt services.
The operational impact of this vulnerability extends beyond simple service disruption, as it fundamentally compromises the availability and integrity of the web rendering service. When an unauthorized attacker successfully accesses the shutdown endpoint, they can immediately terminate all active rendering processes, causing cascading failures throughout dependent systems that rely on Rendertron for content delivery. This vulnerability particularly affects web applications that depend on server-side rendering for proper functionality, potentially leading to complete service outages that impact end users. The attack vector is particularly concerning because it requires minimal technical skill and can be executed through basic web browsing tools, making it accessible to a wide range of threat actors. Organizations using Rendertron 1.0.0 without proper network segmentation or additional authentication layers face significant risk of operational disruption and potential business impact.
Mitigation strategies for CVE-2017-18353 should focus on implementing robust access controls and network security measures to prevent unauthorized access to administrative endpoints. The most direct solution involves adding authentication mechanisms to the _ah/stop route, requiring valid credentials before allowing service shutdown operations. Network-level protections such as firewall rules and access control lists should be implemented to restrict access to administrative endpoints to trusted IP addresses or networks. Organizations should also consider implementing rate limiting and monitoring for unusual access patterns to the shutdown endpoint, which could indicate attempted exploitation. The remediation process should include upgrading to a patched version of Rendertron if available, or implementing proper authentication middleware to protect administrative routes. Additionally, regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other application endpoints. System administrators should also establish logging and alerting mechanisms specifically for administrative function access to detect and respond to potential exploitation attempts.