CVE-2023-7078 in miniflare
Summary
by MITRE • 12/29/2023
Sending specially crafted HTTP requests to Miniflare's server could result in arbitrary HTTP and WebSocket requests being sent from the server. If Miniflare was configured to listen on external network interfaces (as was the default in wrangler until 3.19.0), an attacker on the local network could access other local servers.
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Analysis
by VulDB Data Team • 01/21/2024
The vulnerability identified as CVE-2023-7078 represents a critical server-side request forgery (SSRF) flaw within Miniflare, a popular local development server for Cloudflare Workers. This vulnerability stems from insufficient input validation and sanitization of HTTP request parameters, allowing attackers to manipulate the server's behavior through crafted requests. The flaw specifically affects Miniflare's handling of HTTP and WebSocket requests, where the server fails to properly validate or restrict the destinations of outgoing requests initiated by the application. The vulnerability is particularly concerning because Miniflare was configured to listen on external network interfaces by default in wrangler versions prior to 3.19.0, creating an attack surface that exposes local network services to unauthorized access.
The technical implementation of this vulnerability involves the manipulation of request routing mechanisms within Miniflare's server-side processing pipeline. When properly crafted HTTP requests are sent to the vulnerable Miniflare instance, the server executes arbitrary HTTP and WebSocket requests on behalf of the attacker. This occurs due to inadequate validation of request parameters that should normally be restricted to specific domains or IP addresses. The flaw can be categorized under CWE-918, Server-Side Request Forgery, which describes vulnerabilities where an attacker can manipulate a server into making requests to arbitrary destinations. The vulnerability allows attackers to bypass normal network restrictions and potentially access internal services that would otherwise be protected by network segmentation. The attack vector specifically leverages the fact that Miniflare's default configuration permits external network access, creating a direct pathway for local network reconnaissance and exploitation.
The operational impact of this vulnerability extends beyond simple data exfiltration to encompass comprehensive network reconnaissance and potential lateral movement within local network environments. An attacker positioned on the local network can leverage this vulnerability to enumerate and access other services running on the same network segment, including but not limited to internal web applications, databases, and administrative interfaces. This creates a significant risk for development environments where Miniflare is commonly used, as these environments often contain sensitive development data and may have less restrictive security controls compared to production environments. The vulnerability effectively transforms the Miniflare development server into a potential attack platform for network reconnaissance, allowing attackers to map internal network topology and identify potential targets for further exploitation. The impact is particularly severe in environments where developers have access to production-like data and configurations during development, as this could lead to unauthorized access to sensitive information and systems.
Mitigation strategies for CVE-2023-7078 should focus on both immediate configuration changes and long-term architectural improvements. The most direct remediation involves updating Miniflare to versions that properly restrict external network access and implement proper input validation for HTTP request parameters. Organizations should configure Miniflare to listen only on localhost interfaces when possible, eliminating the default external network exposure that enables this attack. Network segmentation and firewall rules should be implemented to restrict access to Miniflare instances, particularly in development environments where the vulnerability is most likely to be exploited. Additionally, implementing proper request validation and sanitization mechanisms within the application code can prevent malicious request parameters from being processed. The vulnerability aligns with ATT&CK technique T1071.004 for application layer protocol and T1046 for network service discovery, highlighting the need for comprehensive network monitoring and access control policies. Organizations should also consider implementing network-based intrusion detection systems to monitor for suspicious outbound requests that may indicate exploitation attempts. Regular security assessments and penetration testing of development environments can help identify and remediate similar vulnerabilities before they can be exploited by malicious actors.