CVE-2009-0692 in DHCP
Summary
by MITRE
Stack-based buffer overflow in the script_write_params method in client/dhclient.c in ISC DHCP dhclient 4.1 before 4.1.0p1, 4.0 before 4.0.1p1, 3.1 before 3.1.2p1, 3.0, and 2.0 allows remote DHCP servers to execute arbitrary code via a crafted subnet-mask option.
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Analysis
by VulDB Data Team • 12/14/2024
The vulnerability identified as CVE-2009-0692 represents a critical stack-based buffer overflow in the ISC DHCP client software that affects multiple versions including 2.0, 3.0, 3.1.2p1, 4.0.1p1, and 4.1.0p1. This flaw exists within the script_write_params method located in the client/dhclient.c file, making it a significant security concern for systems relying on DHCP client functionality. The vulnerability specifically targets the handling of subnet-mask options received from remote DHCP servers, creating a pathway for remote code execution attacks. The buffer overflow occurs when the client processes malformed subnet-mask option data, causing the program to write beyond the allocated stack buffer space and potentially overwrite adjacent memory locations.
The technical nature of this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent stack memory. The flaw operates through a classic remote exploitation vector where malicious DHCP servers can craft specially formatted subnet-mask options to trigger the buffer overflow. When the dhclient processes these crafted options, the overflow corrupts the stack frame, potentially allowing an attacker to overwrite return addresses, function pointers, or other critical control data structures. This type of vulnerability is particularly dangerous because it can be exploited without requiring local access to the target system, making it a prime candidate for network-based attacks.
The operational impact of this vulnerability extends beyond simple privilege escalation as it enables full remote code execution capabilities on systems running vulnerable DHCP client implementations. Attackers can leverage this vulnerability to gain complete control over affected systems, potentially leading to data breaches, privilege escalation, or further network infiltration. The vulnerability affects systems across multiple ISC DHCP client versions, indicating a widespread exposure that could impact enterprise networks, home routers, and various network infrastructure components that rely on DHCP client functionality. The attack surface is particularly broad given that DHCP clients are ubiquitous in networked environments, making the potential impact of exploitation significant for organizations of all sizes.
Mitigation strategies for CVE-2009-0692 should prioritize immediate patching of all affected ISC DHCP client versions to the latest stable releases that contain the necessary security fixes. Organizations should also implement network segmentation and DHCP server authentication mechanisms to reduce the risk of malicious DHCP servers within their networks. Additional protective measures include deploying network monitoring solutions to detect anomalous DHCP traffic patterns and implementing proper access controls to limit which systems can act as DHCP servers. The vulnerability demonstrates the importance of input validation and bounds checking in network protocol implementations, aligning with ATT&CK technique T1059.007 for command and scripting interpreter execution. Security teams should also consider implementing intrusion detection systems that can identify and alert on potential exploitation attempts targeting this specific vulnerability class.