CVE-2003-0026 in DHCPD
Summary
by MITRE
Multiple stack-based buffer overflows in the error handling routines of the minires library, as used in the NSUPDATE capability for ISC DHCPD 3.0 through 3.0.1RC10, allow remote attackers to execute arbitrary code via a DHCP message containing a long hostname.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 11/18/2024
The vulnerability described in CVE-2003-0026 represents a critical stack-based buffer overflow flaw within the minires library error handling mechanisms of ISC DHCPD versions 3.0 through 3.0.1RC10. This issue specifically affects the NSUPDATE capability which enables dynamic DNS updates through DHCP messages. The vulnerability arises from inadequate input validation and buffer management in the error handling routines that process DHCP messages containing excessively long hostnames. When a malicious attacker crafts a DHCP message with an oversized hostname field, the minires library fails to properly bounds-check the input data before copying it into fixed-size stack buffers, creating exploitable conditions that can lead to arbitrary code execution.
The technical exploitation of this vulnerability occurs through a stack-based buffer overflow attack pattern that aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent stack memory locations. The flaw specifically manifests when the NSUPDATE functionality processes DHCP messages containing hostnames that exceed the allocated buffer space, causing the program to overwrite stack contents including return addresses and saved registers. This type of vulnerability falls under the ATT&CK technique T1059.007 for Command and Scripting Interpreter, as successful exploitation can provide attackers with remote code execution capabilities. The error handling routines in minires demonstrate poor defensive programming practices where the library does not implement proper input sanitization or length validation before processing network data.
The operational impact of CVE-2003-0026 is severe and far-reaching within network infrastructure environments that utilize ISC DHCPD with NSUPDATE enabled. Attackers can remotely compromise systems by simply sending malicious DHCP messages to affected servers, requiring no authentication or specialized access privileges. This vulnerability essentially transforms any network-connected device that processes DHCP messages into a potential attack vector, allowing adversaries to execute arbitrary code with the privileges of the DHCP server process. The implications extend beyond simple system compromise, as successful exploitation could enable attackers to gain persistent access to network infrastructure, potentially leading to complete network takeover or lateral movement within the organization's network environment.
Mitigation strategies for this vulnerability require immediate patching of affected ISC DHCPD versions to either the 3.0.2 release or later, as the maintainers addressed this specific buffer overflow issue through proper bounds checking and input validation in the minires library error handling routines. Organizations should also implement network segmentation and access controls to limit exposure of DHCP servers to untrusted networks, while monitoring DHCP traffic for anomalous hostname lengths that might indicate exploitation attempts. Additionally, network administrators should consider disabling NSUPDATE functionality if it is not essential for their operations, as this removes the attack surface entirely. The remediation process should include comprehensive vulnerability scanning to identify all affected systems and thorough testing of patched versions to ensure that the fix does not introduce regressions in DHCP service functionality. Security teams should also establish monitoring procedures to detect potential exploitation attempts through abnormal DHCP message patterns and implement network-based intrusion detection systems that can identify and block malicious DHCP traffic containing oversized hostnames.