CVE-2002-0702 in DHCPD
Summary
by MITRE
Format string vulnerabilities in the logging routines for dynamic DNS code (print.c) of ISC DHCP daemon (DHCPD) 3 to 3.0.1rc8, with the NSUPDATE option enabled, allow remote malicious DNS servers to execute arbitrary code via format strings in a DNS server response.
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Analysis
by VulDB Data Team • 10/25/2024
The vulnerability identified as CVE-2002-0702 represents a critical format string vulnerability within the ISC DHCP daemon version 3.0.0 through 3.0.1rc8, specifically affecting systems with the NSUPDATE option enabled. This flaw resides in the dynamic DNS code logging routines located in the print.c file, where improper handling of format specifiers in user-supplied input creates a path for remote code execution. The vulnerability manifests when the DHCP daemon processes DNS server responses containing malicious format strings, particularly in environments where the daemon is configured to perform dynamic DNS updates.
The technical exploitation of this vulnerability occurs through the manipulation of DNS server responses that contain format string specifiers such as %s, %n, or %x within the logging mechanisms. When the DHCP daemon processes these malformed responses, the format string vulnerabilities in the logging code allow attackers to control the execution flow of the daemon process. This type of vulnerability is classified as CWE-134, which specifically addresses the use of format strings without proper validation, and aligns with ATT&CK technique T1059.007 for command and script injection. The vulnerability is particularly dangerous because it allows remote attackers to execute arbitrary code with the privileges of the DHCP daemon process, potentially leading to full system compromise.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with the capability to manipulate the DHCP service itself, potentially disrupting network operations or gaining persistent access to the network infrastructure. Systems utilizing the NSUPDATE option are particularly at risk since this feature enables the DHCP daemon to update DNS records dynamically, creating additional attack surface where malicious DNS responses can be crafted to exploit the format string vulnerability. The vulnerability affects the core functionality of the DHCP daemon, making it a critical concern for network administrators who rely on ISC DHCP for network infrastructure management. Organizations running affected versions of the DHCP daemon with NSUPDATE enabled face significant risk of unauthorized access and potential network-wide compromise.
Mitigation strategies for this vulnerability include immediate upgrading to ISC DHCP version 3.0.1 or later, where the format string vulnerabilities have been addressed through proper input validation and sanitization of logging routines. Network administrators should also consider disabling the NSUPDATE option if it is not essential for their operations, as this removes the attack vector entirely. Additionally, implementing proper network segmentation and monitoring for unusual DNS traffic patterns can help detect potential exploitation attempts. The vulnerability demonstrates the importance of secure coding practices in network infrastructure software, particularly regarding input validation and format string handling, and serves as a reminder of the critical need for regular security updates in mission-critical network services. Organizations should also implement network-based intrusion detection systems to monitor for potential exploitation attempts targeting this specific vulnerability.