CVE-2011-3596 in Polipo
Summary
by MITRE
Polipo before 1.0.4.1 suffers from a DoD vulnerability via specially-crafted HTTP POST / PUT request.
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Analysis
by VulDB Data Team • 10/19/2024
The vulnerability identified as CVE-2011-3596 affects Polipo versions prior to 1.0.4.1 and represents a denial of service condition that can be triggered through specifically crafted HTTP POST and PUT requests. This vulnerability resides within the HTTP proxy server implementation and demonstrates a critical flaw in request processing that allows remote attackers to disrupt service availability. The issue stems from insufficient validation of HTTP request parameters and headers, particularly when handling POST and PUT methods that are commonly used for data submission in web applications.
The technical implementation flaw occurs within the request parsing and handling mechanisms of Polipo's HTTP server component. When processing specially crafted HTTP POST or PUT requests, the proxy server fails to properly validate input parameters, leading to a condition where malformed or oversized request data can cause the service to crash or become unresponsive. This vulnerability operates at the application layer and can be exploited without authentication, making it particularly dangerous in environments where the proxy server is accessible to untrusted networks. The flaw essentially creates a resource exhaustion scenario where the server process becomes unable to handle additional legitimate requests due to improper error handling.
From an operational perspective, this vulnerability presents significant risks to organizations relying on Polipo as an HTTP proxy solution. The denial of service condition can result in complete service disruption for users attempting to access web resources through the proxy, potentially affecting hundreds or thousands of concurrent users depending on the scale of deployment. The impact extends beyond simple service interruption as it can affect business continuity and user productivity, particularly in environments where the proxy serves as a critical infrastructure component. Network administrators may experience difficulty in diagnosing the root cause since the service appears to crash rather than gracefully handle the malformed requests, leading to extended downtime and potential security incident response complications.
Organizations should prioritize immediate remediation by upgrading to Polipo version 1.0.4.1 or later, which contains the necessary patches to address the malformed request handling issue. Additionally, implementing network-level protections such as rate limiting and request filtering can provide temporary mitigation while upgrades are being deployed. The vulnerability aligns with CWE-400, which covers "Uncontrolled Resource Consumption," and demonstrates characteristics consistent with ATT&CK technique T1499.004 for "Endpoint Denial of Service." Network monitoring should be enhanced to detect unusual patterns in HTTP request processing that may indicate exploitation attempts, and regular security assessments should verify that proxy configurations properly validate incoming requests. Given the nature of the vulnerability, implementing proper input validation and error handling mechanisms at the application layer provides the most effective long-term solution to prevent similar issues in other components of the system architecture.