CVE-2023-29552 in Service Location Protocol
Summary
by MITRE • 04/25/2023
The Service Location Protocol (SLP, RFC 2608) allows an unauthenticated, remote attacker to register arbitrary services. This could allow the attacker to use spoofed UDP traffic to conduct a denial-of-service attack with a significant amplification factor.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 01/29/2025
The Service Location Protocol version 2 as defined in RFC 2608 suffers from a critical security vulnerability that enables unauthenticated remote attackers to register arbitrary services within network environments. This fundamental flaw exists in the protocol's design where no authentication mechanisms are implemented to verify the legitimacy of service registration requests, creating an exploitable entry point for malicious actors. The vulnerability specifically affects the SLP daemon implementations across various operating systems including but not limited to Linux, Windows, and Unix-based systems that support the SLP protocol. The absence of authentication requirements means that any remote attacker with network access can submit service registration messages without providing valid credentials or authorization, fundamentally undermining the security model of the protocol.
The technical exploitation of this vulnerability leverages the inherent design of SLP's service registration mechanism where service advertisements are accepted without verification of the sender's identity or authorization status. Attackers can craft and inject spoofed UDP packets containing malicious service registration requests that appear to originate from legitimate network endpoints. These spoofed packets exploit the protocol's trust model where service location agents accept registration messages based solely on the presence of valid SLP headers and service information, without validating the authenticity of the service provider. The protocol's lack of message authentication codes or cryptographic verification mechanisms means that attackers can easily forge service registration data, leading to the creation of false service entries within the SLP directory service. This vulnerability operates at the network layer and affects the core functionality of service discovery mechanisms that rely on SLP for dynamic service registration and location.
The operational impact of this vulnerability is severe and multifaceted, particularly when considering the potential for amplification attacks that can significantly overwhelm network resources and service availability. An attacker can leverage the SLP protocol's design to conduct denial-of-service attacks by registering multiple fake services that consume directory service resources and create network congestion. The amplification factor can be substantial as a single attacker packet can generate multiple responses from service location agents, potentially creating a scenario where small amounts of malicious traffic generate massive amounts of network response traffic. This capability allows attackers to disrupt legitimate service discovery operations, consume network bandwidth, and exhaust system resources of devices running SLP implementations. The vulnerability also creates potential for service poisoning attacks where legitimate services may be obscured or replaced by malicious entries, leading to confusion in service location and potential redirection of network traffic to malicious endpoints.
Network security professionals should implement immediate mitigations to address this vulnerability, including network segmentation to isolate SLP-enabled systems from untrusted networks, firewall rules to restrict UDP traffic on SLP ports, and the implementation of network monitoring to detect anomalous service registration patterns. The protocol should be configured to disable service registration functionality when not required, and network administrators should consider deploying intrusion detection systems that can identify and alert on suspicious SLP traffic patterns. Organizations should also evaluate their SLP implementations for authentication mechanisms and consider upgrading to more secure service discovery protocols such as DNS-SD or mDNS with proper authentication. According to CWE standards, this vulnerability maps to CWE-284 which addresses insufficient access control, and aligns with ATT&CK technique T1071.004 for application layer protocol usage in service location protocols. The mitigation strategy should also include regular security audits of network services, implementation of network access control lists, and the deployment of network behavior monitoring tools to detect unauthorized service registration attempts that could indicate exploitation of this vulnerability.