CVE-2001-0838 in Rwhoisd
Summary
by MITRE
Format string vulnerability in Network Solutions Rwhoisd 1.5.x allows remote attackers execute arbitrary code via format string specifiers in the -soa command.
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Analysis
by VulDB Data Team • 10/04/2025
The vulnerability identified as CVE-2001-0838 represents a critical format string vulnerability within Network Solutions Rwhoisd version 1.5.x, a domain name server implementation that provides whois services for network solutions. This flaw exists in the command processing mechanism where the software fails to properly validate input parameters before using them in format string operations. The specific vulnerability manifests when the -soa command is invoked with maliciously crafted input containing format string specifiers that are not properly sanitized or escaped. This vulnerability falls under the CWE-134 category of Use of Externally-Controlled Format String, which is a well-documented weakness in software security practices that allows attackers to manipulate how strings are formatted and displayed.
The technical exploitation of this vulnerability occurs when a remote attacker sends specially crafted input to the rwhoisd service through the -soa command interface. When the application processes this input without proper validation, it passes the user-controlled data directly to a printf-like function, enabling the attacker to inject format specifiers that can read from memory locations or write data to arbitrary memory addresses. This type of vulnerability can lead to complete system compromise, allowing attackers to execute arbitrary code with the privileges of the rwhoisd process. The ATT&CK framework categorizes this as a command injection technique under the T1059.002 sub-technique, where attackers leverage application vulnerabilities to execute malicious commands in the target environment. The vulnerability is particularly dangerous because it operates at the application level and can be exploited without requiring authentication, making it a prime target for automated exploitation tools.
The operational impact of this vulnerability extends beyond simple code execution to include potential data breaches, system compromise, and service disruption within network infrastructure. When exploited successfully, attackers can gain unauthorized access to sensitive network information, escalate privileges, and potentially establish persistent backdoors within the affected systems. The rwhoisd service typically runs with elevated privileges to access network information, making successful exploitation particularly dangerous. Organizations using this software are at risk of having their network topology, IP address ranges, and other sensitive information exposed to attackers. The vulnerability also impacts the overall security posture of networks that rely on this service, as it can serve as a foothold for broader attacks within the network infrastructure. The lack of proper input validation in the command processing layer creates a fundamental security weakness that can be exploited across multiple network segments.
Mitigation strategies for CVE-2001-0838 require immediate action including patching the affected rwhoisd software to version 1.5.2 or later, which contains the necessary input validation fixes. Organizations should implement network segmentation to limit access to the rwhoisd service to only trusted administrative networks, and consider disabling the service entirely if it is not required for operations. Network monitoring should be enhanced to detect unusual patterns of whois queries that might indicate exploitation attempts, and intrusion detection systems should be configured to alert on suspicious format string patterns. Additionally, implementing proper access controls and privilege separation ensures that even if exploitation occurs, the attacker's capabilities are limited. The remediation process should include comprehensive vulnerability scanning to identify all instances of the vulnerable software, and organizations should consider migrating to more modern and secure whois server implementations that follow current security best practices. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other network services that may be susceptible to format string attacks.