CVE-2011-2717 in DHCPv6 Client
Summary
by MITRE
The DHCPv6 client (dhcp6c) as used in the dhcpv6 project through 2011-07-25 allows remote DHCP servers to execute arbitrary commands via shell metacharacters in a hostname obtained from a DHCP message.
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Analysis
by VulDB Data Team • 03/04/2025
The vulnerability identified as CVE-2011-2717 represents a critical command injection flaw within the DHCPv6 client implementation known as dhcp6c. This vulnerability affects the dhcpv6 project through the specific date of 2011-07-25 and demonstrates a fundamental security weakness in how the client processes hostname information received from remote DHCP servers. The flaw occurs when the DHCPv6 client receives a hostname parameter in a DHCP message and fails to properly sanitize this input before using it in shell operations, creating an avenue for remote attackers to execute arbitrary commands on the affected system.
The technical exploitation of this vulnerability stems from improper input validation within the DHCPv6 client's processing logic. When dhcp6c receives a DHCP message containing a hostname field, it directly incorporates this value into shell commands without adequate sanitization or escaping mechanisms. This design flaw allows attackers who control remote DHCP servers to inject shell metacharacters such as semicolons, pipes, or backticks into the hostname field, which then get executed as shell commands when the client processes the DHCP response. The vulnerability is classified under CWE-78 as a "Improper Neutralization of Special Elements used in an OS Command" which directly maps to the command injection pattern where user-controllable input is improperly handled in shell contexts.
The operational impact of CVE-2011-2717 is severe and far-reaching across network environments that rely on DHCPv6 for address allocation and configuration. An attacker who gains control of a DHCP server or can perform man-in-the-middle attacks against DHCPv6 communications can remotely execute arbitrary commands with the privileges of the dhcp6c process, typically running with elevated privileges. This could lead to complete system compromise, allowing attackers to install backdoors, exfiltrate data, or establish persistent access to the affected network infrastructure. The vulnerability is particularly dangerous in environments where DHCPv6 clients are automatically configured and where network administrators trust DHCP responses without additional verification mechanisms.
Mitigation strategies for CVE-2011-2717 should focus on both immediate patching and operational security improvements. The primary solution involves updating to a patched version of the dhcpv6 project where proper input sanitization has been implemented to prevent shell metacharacters from being executed. Organizations should also implement network segmentation to limit the exposure of DHCPv6 clients to untrusted networks and consider deploying DHCP snooping mechanisms to prevent unauthorized DHCP servers from operating on the network. From an ATT&CK framework perspective, this vulnerability maps to techniques involving command injection and privilege escalation, with potential for lateral movement once initial compromise is achieved through the exploitation of the DHCPv6 client vulnerability. Network administrators should also consider implementing additional monitoring and alerting for unusual DHCP activity and shell command execution patterns that could indicate exploitation attempts.