CVE-2004-1006 in DHCPD
Summary
by MITRE
Format string vulnerability in the log functions in dhcpd for dhcp 2.x allows remote DNS servers to execute arbitrary code via certain DNS messages, a different vulnerability than CVE-2002-0702.
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Analysis
by VulDB Data Team • 07/07/2025
The vulnerability described in CVE-2004-1006 represents a critical format string flaw within the dhcpd daemon version 2.x series that specifically affects the logging functions. This security weakness enables remote attackers to manipulate the format string parameters used in log message generation, creating a pathway for arbitrary code execution. The vulnerability operates through DNS messages that are processed by the dhcpd service, making it particularly dangerous in network environments where DHCP and DNS services interact. Unlike CVE-2002-0702 which addressed different aspects of DNS handling, this flaw specifically targets the string formatting mechanisms within the logging subsystem of the DHCP server implementation.
The technical exploitation of this vulnerability occurs when the dhcpd daemon processes malformed DNS responses containing specially crafted format specifiers within the DNS message data. When these messages are logged through vulnerable format string functions, the server fails to properly validate or sanitize the input before passing it to the printf family of functions. This allows attackers to inject format specifiers that can cause the logging function to read from arbitrary memory locations or write data to specific memory addresses, effectively enabling code execution with the privileges of the dhcpd process. The vulnerability falls under the CWE-134 weakness category, which specifically addresses the use of untrusted data in format string operations, making it a well-documented and dangerous class of vulnerability.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass potential complete system compromise when the dhcpd service runs with elevated privileges. Network administrators who rely on DHCP services for network infrastructure management face significant risk as attackers can leverage this vulnerability to gain unauthorized access to network resources, potentially leading to man-in-the-middle attacks, network disruption, or data exfiltration. The vulnerability's remote nature means that attackers do not require physical access or local network presence to exploit the flaw, making it particularly dangerous in environments where DHCP services are exposed to untrusted networks. This weakness aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation, as successful exploitation typically results in elevated system privileges and persistent access.
Mitigation strategies for CVE-2004-1006 require immediate patching of affected dhcpd versions to address the format string vulnerability in logging functions. Organizations should implement network segmentation to limit access to DHCP services, particularly by restricting DNS server access to trusted network segments. The use of intrusion detection systems capable of identifying malformed DNS traffic patterns can provide additional monitoring capabilities. Network administrators should also consider implementing proper access controls and firewall rules that restrict communication between DHCP servers and untrusted DNS servers. Regular security audits of network infrastructure components and vulnerability assessments should be conducted to identify similar format string vulnerabilities in other network services. Additionally, implementing proper input validation and sanitization practices within all network services, combined with regular security updates and patches, forms the foundation of defense against such exploitation vectors that leverage the fundamental weakness of improper format string handling in system applications.