CVE-2000-0743 in Gopherd
Summary
by MITRE
Buffer overflow in University of Minnesota (UMN) gopherd 2.x allows remote attackers to execute arbitrary commands via a DES key generation request (GDESkey) that contains a long ticket value.
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Analysis
by VulDB Data Team • 10/12/2025
The vulnerability identified as CVE-2000-0743 represents a critical buffer overflow flaw within the University of Minnesota gopherd 2.x web server implementation that operates within the gopher protocol framework. This vulnerability specifically targets the DES key generation functionality where the server processes GDESkey requests containing ticket values. The gopher protocol, while largely obsolete today, was once a prevalent method for information retrieval on the internet and formed the foundation for many early web services. The affected gopherd 2.x implementation demonstrates a classic buffer overflow condition that occurs when processing user-supplied data without adequate bounds checking, creating an exploitable condition that can be leveraged by remote attackers to execute arbitrary code on the affected system.
The technical nature of this vulnerability stems from improper input validation within the DES key generation routine where the server fails to properly constrain the length of ticket values passed in GDESkey requests. When an attacker submits a malformed request containing an excessively long ticket value, the server's buffer allocation mechanism cannot accommodate the oversized input, resulting in memory corruption that overflows into adjacent memory segments. This buffer overflow condition allows attackers to overwrite critical program execution data including return addresses and function pointers, enabling them to redirect program flow and execute malicious code with the privileges of the gopherd process. The vulnerability operates at the application layer and requires no authentication, making it particularly dangerous as it can be exploited remotely over the network without any prior access credentials.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete system compromise and potential denial of service conditions. Successful exploitation can provide attackers with full control over the affected gopherd server, enabling them to access sensitive data, modify system configurations, install persistent backdoors, or use the compromised system as a launch point for further attacks against the internal network. The gopher protocol's role in early internet infrastructure means that vulnerable systems could serve as entry points for broader network infiltration, particularly in environments where legacy systems were still operational. Additionally, the vulnerability's remote exploitability without authentication creates a significant risk for organizations that have not properly updated their services or maintained inventory of legacy applications.
Mitigation strategies for CVE-2000-0743 should prioritize immediate patching and system updates to address the underlying buffer overflow condition in gopherd 2.x implementations. Organizations must ensure all affected systems are updated to patched versions of the gopherd software that include proper input validation and bounds checking mechanisms. Network segmentation and access control measures should be implemented to restrict access to gopher services, particularly in environments where these legacy protocols are still operational. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which represents a well-documented class of vulnerabilities that have been extensively studied within cybersecurity frameworks. From an attack perspective, this vulnerability would map to ATT&CK techniques involving remote code execution and privilege escalation, as attackers can leverage the overflow to gain elevated system privileges. System administrators should also conduct comprehensive audits of legacy services to identify and decommission any remaining gopherd implementations, as the protocol itself has been largely deprecated in favor of more secure web protocols. Regular security assessments and vulnerability scanning should be implemented to identify similar buffer overflow conditions in other legacy applications that may be running on the network infrastructure.