CVE-2001-0129 in Tinyproxy
Summary
by MITRE
Buffer overflow in Tinyproxy HTTP proxy 1.3.3 and earlier allows remote attackers to cause a denial of service and possibly execute arbitrary commands via a long connect request.
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Analysis
by VulDB Data Team • 10/08/2025
The vulnerability identified as CVE-2001-0129 represents a critical buffer overflow flaw in Tinyproxy HTTP proxy versions 1.3.3 and earlier. This issue resides within the proxy server's handling of CONNECT requests, which are commonly used in HTTP tunneling operations to establish secure connections through proxy servers. The vulnerability stems from inadequate input validation and bounds checking when processing the CONNECT method, specifically in how the software manages the hostname portion of these requests.
The technical exploitation of this buffer overflow occurs when a remote attacker sends a specially crafted HTTP CONNECT request containing an excessively long hostname string. The Tinyproxy software fails to properly validate the length of the incoming data before copying it into a fixed-size buffer, leading to memory corruption that can overwrite adjacent memory locations. This memory corruption can potentially overwrite critical program variables, return addresses, or function pointers, which may result in unpredictable program behavior and system instability. The vulnerability specifically aligns with CWE-121, which categorizes buffer overflow conditions where insufficient boundary checking allows data to be written beyond the allocated buffer space.
The operational impact of this vulnerability extends beyond simple denial of service conditions. While the primary effect manifests as a system crash or restart causing denial of service, the potential for arbitrary code execution presents a more severe threat to system security. When the buffer overflow corrupts the return address or execution flow of the program, attackers can potentially inject and execute malicious code within the context of the proxy service. This could allow unauthorized access to the underlying system, privilege escalation, or further compromise of network infrastructure. The vulnerability affects the availability and integrity aspects of the CIA triad, as it can disrupt service availability while potentially compromising system integrity through code execution.
Organizations utilizing Tinyproxy versions prior to 1.3.4 should implement immediate mitigation strategies to address this vulnerability. The primary remediation involves upgrading to Tinyproxy version 1.3.4 or later, which includes proper bounds checking and input validation for CONNECT requests. Network administrators should also consider implementing firewall rules to restrict access to proxy services and monitor for unusual CONNECT request patterns that might indicate exploitation attempts. Additionally, configuring the proxy server to limit the maximum length of hostname strings in CONNECT requests can serve as an additional defensive measure. From an ATT&CK framework perspective, this vulnerability maps to techniques involving buffer overflow exploits and privilege escalation, with potential lateral movement opportunities if successful exploitation occurs. System monitoring should focus on detecting anomalous proxy behavior, unexpected process restarts, and unusual network traffic patterns that might indicate exploitation attempts.