CVE-2002-0930 in NetWare
Summary
by MITRE
Format string vulnerability in the FTP server for Novell Netware 6.0 SP1 (NWFTPD) allows remote attackers to cause a denial of service (ABEND) via format strings in the USER command.
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Analysis
by VulDB Data Team • 05/18/2019
The vulnerability described in CVE-2002-0930 represents a critical format string flaw within the Novell Netware 6.0 SP1 FTP server implementation known as NWFTPD. This particular vulnerability manifests when the server processes the USER command, which is a standard initial command in FTP protocol negotiations used for user authentication. The flaw occurs because the server fails to properly validate or sanitize input parameters before using them in format string operations, creating an exploitable condition that can be leveraged by remote attackers to disrupt service availability.
The technical nature of this vulnerability aligns with CWE-134, which specifically addresses the use of format strings without proper validation or sanitization. When an attacker submits maliciously crafted input containing format specifiers such as %s, %d, or other format string directives as part of the USER command, the NWFTPD server processes these inputs directly without adequate protection mechanisms. This improper handling allows the attacker to manipulate the server's memory layout and potentially trigger abnormal program termination or system instability, resulting in an application crash or system abend.
From an operational impact perspective, this vulnerability presents a significant denial of service risk to organizations relying on Novell Netware 6.0 SP1 FTP services. The remote exploitation capability means that attackers can trigger service disruption from outside the network perimeter without requiring authentication or local access privileges. This makes the vulnerability particularly dangerous as it can be exploited by anyone with network access to the affected FTP server, potentially leading to extended service outages that impact business operations and user access to network resources. The abend condition typically results in immediate service disruption that requires manual intervention to restore normal operations.
The attack vector for this vulnerability follows standard remote exploitation patterns consistent with ATT&CK technique T1499.004 for network denial of service. Attackers can craft malicious USER command inputs containing format string specifiers that, when processed by the vulnerable server, cause memory corruption and subsequent system instability. This vulnerability demonstrates the importance of input validation and proper string handling practices in network service implementations. Organizations should implement immediate mitigations including applying vendor patches, disabling unnecessary FTP services, and implementing network segmentation controls to limit exposure. The vulnerability also highlights the necessity of regular security assessments and code reviews to identify similar format string vulnerabilities in legacy systems that may not have received adequate security updates over time.