CVE-2023-50433 in simple-dhcp-server
Summary
by MITRE • 04/30/2024
marshall in dhcp_packet.c in simple-dhcp-server through ec976d2 allows remote attackers to cause a denial of service by sending a malicious DHCP packet. The crash is caused by a type confusion bug that results in a large memory allocation; when this memory allocation fails the DHCP server will crash.
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Analysis
by VulDB Data Team • 11/02/2024
The vulnerability identified as CVE-2023-50433 represents a critical denial of service flaw within the simple-dhcp-server software suite, specifically affecting the dhcp_packet.c module in versions up to and including ec976d2. This issue manifests when remote attackers craft and transmit specially malformed DHCP packets to the target server, exploiting a fundamental type confusion vulnerability that directly impacts the server's memory management mechanisms. The root cause lies in how the software handles type checking during packet processing, creating a scenario where attacker-controlled input can manipulate the program's execution flow and memory allocation behavior.
The technical implementation of this vulnerability demonstrates a classic type confusion bug that operates at the intersection of memory management and input validation. When a malicious DHCP packet is received, the server's processing logic fails to properly validate the packet structure before attempting to allocate memory based on attacker-controlled values. This type confusion results in the program attempting to allocate an excessively large memory block, far beyond what would normally be required for legitimate DHCP operations. The vulnerability's design aligns with CWE-121, which describes heap-based buffer overflow conditions, and more specifically relates to CWE-704, which covers type confusion in memory management operations.
The operational impact of this vulnerability extends beyond simple service disruption, as it enables remote attackers to reliably crash the DHCP server through minimal network traffic. The denial of service occurs because the memory allocation failure triggers an unhandled exception or program termination, effectively removing the server's ability to provide DHCP services to network clients. This vulnerability particularly affects network infrastructure where DHCP servers are critical for device connectivity, potentially causing widespread network disruption in environments where the server is not properly monitored or protected. The attack requires no authentication and can be executed from any network location capable of sending DHCP packets, making it highly exploitable in both local and remote scenarios.
Mitigation strategies for CVE-2023-50433 should prioritize immediate software updates to versions that address the type confusion vulnerability in dhcp_packet.c. Network administrators should implement monitoring solutions to detect unusual DHCP packet patterns and establish automated alerting for potential exploitation attempts. The implementation of network segmentation and access control lists can help limit exposure by restricting which systems can communicate with the DHCP server. Additionally, deploying intrusion detection systems with signature-based detection for known malicious DHCP packet patterns provides an additional layer of protection. Organizations should also consider implementing redundant DHCP servers and failover mechanisms to maintain network connectivity during potential exploitation attempts, while maintaining regular security assessments to identify similar vulnerabilities in other network infrastructure components. The ATT&CK framework categorizes this vulnerability under T1499.004 for network denial of service and T1595.001 for network scanning, emphasizing the need for comprehensive defensive measures that address both the immediate threat and potential follow-on attacks.