CVE-2025-23217 in mitmproxy
Summary
by MITRE • 02/06/2025
mitmproxy is a interactive TLS-capable intercepting HTTP proxy for penetration testers and software developers and mitmweb is a web-based interface for mitmproxy. In mitmweb 11.1.1 and below, a malicious client can use mitmweb's proxy server (bound to `*:8080` by default) to access mitmweb's internal API (bound to `127.0.0.1:8081` by default). In other words, while the cannot access the API directly, they can access the API through the proxy. An attacker may be able to escalate this SSRF-style access to remote code execution. The mitmproxy and mitmdump tools are unaffected. Only mitmweb is affected. This vulnerability has been fixed in mitmproxy 11.1.2 and above. Users are advised to upgrade. There are no known workarounds for this vulnerability.
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Analysis
by VulDB Data Team • 02/06/2025
The vulnerability identified as CVE-2025-23217 affects mitmweb, the web-based interface component of the mitmproxy suite, which serves as an interactive TLS-capable intercepting HTTP proxy widely utilized by penetration testers and software developers. This flaw exists in mitmweb versions 11.1.1 and earlier, where the proxy server operates on the default port 8080 while maintaining an internal API service bound to 127.0.0.1:8081. The security issue stems from improper access controls that allow malicious clients to leverage the proxy server as a conduit to reach the internally bound API endpoint, effectively bypassing the intended network isolation.
The technical exploitation of this vulnerability involves a server-side request forgery (SSRF) attack pattern that leverages the proxy's functionality to access localhost services that should remain inaccessible to external clients. This represents a classic case of insecure direct object references where the proxy server acts as an intermediary that can be manipulated to route requests to internal services that are normally protected by network segmentation. The vulnerability falls under CWE-284, which addresses inadequate access control mechanisms, and demonstrates how proxy servers can inadvertently create attack vectors when they fail to properly validate and sanitize request routing.
The operational impact of this vulnerability is significant as it creates a potential path for remote code execution when attackers can leverage the internal API access to manipulate mitmweb's functionality. While the internal API itself may not directly execute code, it likely provides administrative interfaces that could be used to modify proxy behavior, access captured traffic, or potentially trigger other exploitable components within the application. This type of vulnerability aligns with ATT&CK technique T1190, which describes the use of proxy servers for lateral movement and privilege escalation.
Mitigation efforts must focus on upgrading to mitmproxy version 11.1.2 or later, as this represents the official fix that addresses the access control bypass. The vulnerability is specific to mitmweb and does not affect the core mitmproxy or mitmdump tools, making it a targeted issue within the software suite. Organizations using affected versions should immediately implement this upgrade without delay, as no effective workarounds exist for this particular vulnerability. The fix likely involves implementing proper network isolation controls to prevent the proxy server from acting as an intermediary to localhost services, ensuring that external requests cannot be redirected to internal API endpoints. Security teams should also review their network configurations to verify that the proxy server's access controls are properly configured and that internal services remain appropriately isolated from external network access.