CVE-2013-6230 in BIND
Summary
by MITRE
The Winsock WSAIoctl API in Microsoft Windows Server 2008, as used in ISC BIND 9.6-ESV before 9.6-ESV-R10-P1, 9.8 before 9.8.6-P1, 9.9 before 9.9.4-P1, 9.9.3-S1, 9.9.4-S1, and other products, does not properly support the SIO_GET_INTERFACE_LIST command for netmask 255.255.255.255, which allows remote attackers to bypass intended IP address restrictions by leveraging misinterpretation of this netmask as a 0.0.0.0 netmask.
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Analysis
by VulDB Data Team • 12/23/2024
The vulnerability described in CVE-2013-6230 represents a critical flaw in the Windows Sockets API implementation that affects both Microsoft Windows Server 2008 and various versions of ISC BIND DNS software. This issue stems from improper handling of the SIO_GET_INTERFACE_LIST command when processing netmask 255.255.255.255, creating a significant security bypass mechanism that undermines network access controls and IP address restrictions. The flaw exists at the kernel level within the Winsock subsystem, specifically in how it interprets and processes network interface information through the WSAIoctl API call.
The technical root cause of this vulnerability lies in the misinterpretation of the subnet mask 255.255.255.255, which should represent a single host address in CIDR notation, but is incorrectly processed as a 0.0.0.0 netmask by the affected systems. This misinterpretation occurs during the interface list retrieval process where the system fails to properly validate or normalize the netmask value before applying it to access control decisions. The flaw demonstrates a classic case of improper input validation and handling, aligning with CWE-20: Improper Input Validation and CWE-122: Heap-based Buffer Overflow in the context of network interface processing. The vulnerability essentially allows attackers to manipulate the network interface enumeration process to bypass intended restrictions on IP address access.
The operational impact of this vulnerability extends beyond simple network enumeration, as it provides attackers with a mechanism to circumvent IP-based access controls that are fundamental to network security. When exploited, this flaw enables remote attackers to bypass restrictions that would normally prevent access to specific IP addresses or network segments, potentially allowing unauthorized access to services or resources that should be protected by IP filtering. The vulnerability affects systems that rely on network interface enumeration for access control decisions, making it particularly dangerous in environments where IP-based restrictions are used as security controls. Attackers can leverage this weakness to gain access to systems or services that would otherwise be protected by properly configured IP restrictions, effectively nullifying network-level access controls.
Mitigation strategies for CVE-2013-6230 should focus on both immediate patching and architectural defenses. Organizations must apply the relevant security updates provided by Microsoft for Windows Server 2008 and the ISC BIND software versions affected by this vulnerability. The patches address the underlying implementation issue in the WSAIoctl API handling of netmask values, ensuring proper interpretation and validation of subnet mask parameters. Additionally, network administrators should implement layered security controls that do not rely solely on IP-based restrictions, including implementing proper firewall rules, access control lists, and network segmentation. The vulnerability also highlights the importance of proper input validation in system APIs, as defined by the ATT&CK framework's technique T1071.004 for Application Layer Protocol: DNS, where such flaws can be exploited to bypass network security controls. Organizations should conduct thorough network audits to identify systems that may be vulnerable and implement monitoring for unusual interface enumeration patterns that could indicate exploitation attempts.