CVE-2002-0847 in Tinyproxy
Summary
by MITRE
tinyproxy HTTP proxy 1.5.0, 1.4.3, and earlier allows remote attackers to execute arbitrary code via memory that is freed twice (double-free).
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Analysis
by VulDB Data Team • 09/13/2025
The vulnerability identified as CVE-2002-0847 affects tinyproxy HTTP proxy versions 1.5.0 and earlier, including the 1.4.3 release, presenting a critical security flaw that enables remote code execution through a double-free memory corruption issue. This vulnerability arises from improper memory management within the proxy software's handling of network requests, specifically when processing certain HTTP headers or request parameters that trigger the freeing of the same memory block twice. The double-free condition occurs when the software's memory allocator receives multiple free requests for the same memory address, creating a state where the heap memory becomes corrupted and potentially exploitable by malicious actors. Such memory corruption vulnerabilities are particularly dangerous because they can lead to arbitrary code execution, allowing attackers to gain control over the affected system running the proxy service.
The technical flaw manifests in the memory management routines of tinyproxy where certain input validation or request processing logic fails to properly track memory allocations and deallocations. When an attacker crafts a malicious HTTP request containing specially crafted headers or parameters, the proxy processes this input and eventually leads to the same memory block being freed twice through different code paths. This double-free condition creates a heap-based memory corruption that can be leveraged to manipulate the program's execution flow. The vulnerability is classified as a memory corruption issue and aligns with CWE-415, which specifically addresses double free conditions in memory management. This type of vulnerability represents a fundamental flaw in the software's defensive programming practices and demonstrates poor resource management that violates basic security principles.
The operational impact of this vulnerability extends beyond simple remote code execution, as it can enable attackers to compromise the entire system running the affected tinyproxy service. Since HTTP proxies typically operate with elevated privileges to handle network traffic between clients and servers, successful exploitation could provide attackers with access to sensitive network communications, potentially allowing them to intercept, modify, or redirect traffic. The vulnerability affects systems where tinyproxy is deployed as a web proxy, including corporate networks, public internet services, and various network infrastructure components that rely on this proxy software for traffic management. Attackers can exploit this weakness without requiring authentication or specific local access, making it particularly dangerous for publicly accessible proxy services. The attack surface is broad given that tinyproxy is widely used across various operating systems and network configurations, increasing the potential number of vulnerable targets.
Mitigation strategies for CVE-2002-0847 primarily focus on immediate remediation through software updates and patches provided by the vendor. Organizations should prioritize upgrading to tinyproxy versions that have addressed this memory management flaw, typically those released after the vulnerability disclosure. System administrators should also implement network monitoring to detect unusual patterns in HTTP traffic that might indicate exploitation attempts. Additional protective measures include deploying intrusion detection systems that can identify malicious HTTP requests designed to trigger double-free conditions, implementing network segmentation to limit exposure of proxy services, and conducting regular security assessments of proxy configurations. The vulnerability demonstrates the importance of proper memory management practices and adherence to secure coding standards, particularly in network services that handle untrusted input. From an ATT&CK framework perspective, this vulnerability maps to techniques involving memory corruption exploits and remote code execution, highlighting the need for defensive measures against heap-based memory corruption attacks that are commonly used in advanced persistent threat campaigns.