CVE-2017-3752 in Switch
Summary
by MITRE
An industry-wide vulnerability has been identified in the implementation of the Open Shortest Path First (OSPF) routing protocol used on some Lenovo switches. Exploitation of these implementation flaws may result in attackers being able to erase or alter the routing tables of one or many routers, switches, or other devices that support OSPF within a routing domain.
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Analysis
by VulDB Data Team • 11/06/2019
The vulnerability identified as CVE-2017-3752 represents a critical flaw in the Open Shortest Path First routing protocol implementation found on certain Lenovo network switches. This weakness resides in how these devices process OSPF messages, specifically within their handling of routing updates and table modifications. The issue stems from insufficient validation and authentication mechanisms within the OSPF implementation, creating a pathway for malicious actors to manipulate network routing information. Such vulnerabilities are particularly dangerous in enterprise and service provider networks where OSPF is extensively deployed for dynamic routing management. The flaw allows unauthorized parties to inject false routing information into the network, potentially leading to complete disruption of network communications or redirection of traffic through compromised paths.
The technical nature of this vulnerability aligns with CWE-284, which addresses improper access control mechanisms in network protocols. The implementation flaw occurs during the OSPF packet processing phase where devices fail to properly authenticate routing updates or validate the legitimacy of routing table modifications. Attackers can exploit this by crafting specially malformed OSPF packets that appear to originate from legitimate routing peers within the network domain. This type of attack falls under the ATT&CK technique T1072, specifically targeting network protocols and services for lateral movement and privilege escalation. The vulnerability essentially allows for a form of route injection attack where malicious actors can modify or delete routing entries, causing network partitions or creating backdoor paths for further exploitation. The affected Lenovo switches typically process OSPF updates without adequate cryptographic verification or message integrity checks, making them susceptible to man-in-the-middle style attacks within their OSPF routing domains.
The operational impact of CVE-2017-3752 extends far beyond simple network disruption, potentially compromising entire network infrastructures and enabling sophisticated attack scenarios. When exploited, this vulnerability can result in complete routing table corruption, forcing network devices to forward traffic through unintended paths or completely isolate portions of the network. Attackers could leverage this weakness to perform traffic redirection attacks, where sensitive data flows are captured or altered, or execute network denial-of-service conditions that can persist until manual intervention occurs. The vulnerability particularly affects environments where OSPF is used for internal routing within enterprise networks, data centers, or service provider backbones where network reliability and security are paramount. Organizations may experience extended periods of network instability as routing convergence occurs with corrupted information, potentially leading to cascading failures throughout interconnected network segments. The attack surface is broad since OSPF is widely implemented across various network equipment vendors, though Lenovo switches were specifically identified as vulnerable in this particular case, highlighting the importance of vendor-specific security assessments.
Mitigation strategies for CVE-2017-3752 require immediate implementation of network security controls and firmware updates from Lenovo. Organizations should prioritize applying the vendor-provided security patches that address the OSPF implementation flaws and strengthen authentication mechanisms for routing updates. Network segmentation and access control lists should be implemented to limit OSPF peer relationships to trusted network segments only, reducing the attack surface for unauthorized route injection attempts. The deployment of OSPF authentication mechanisms, including MD5 authentication or other cryptographic methods, can help validate routing updates and prevent unauthorized modifications. Network monitoring systems should be enhanced to detect unusual routing table changes or suspicious OSPF packet patterns that may indicate exploitation attempts. Additionally, implementing network intrusion detection systems specifically configured to monitor OSPF traffic can provide early warning of potential attacks. The security community recommends following NIST guidelines for network protocol security and implementing the principle of least privilege for routing protocol configurations. Regular network audits and vulnerability assessments should include specific checks for OSPF implementation weaknesses, particularly in legacy network equipment that may not have received recent security updates. Organizations should also consider implementing network behavior analytics to detect anomalous routing patterns that could indicate successful exploitation of this vulnerability.