Security Experts:

VMware Patches 'Hard-to-Exploit' DoS Vulnerability

An update released by VMware for its NSX-V network virtualization solution patches an important denial-of-service (DoS) vulnerability.

The security hole, tracked as CVE-2017-4920, exists in the OSPF protocol implementation in NSX-V due to it not handling link-state advertisement (LSA) correctly.

“A rogue LSA may exploit this issue resulting in continuous sending of LSAs between two routers eventually going in loop or loss of connectivity,” VMware said in its advisory. “The issue cannot be exploited in case the OSPF protocol is not configured. At setup time, no particular protocol is configured.”

In a separate blog post, the company pointed out that the vulnerability is “hard to exploit.” One mitigating factor is that an attacker requires local access to the targeted system in order to exploit the vulnerability.

The flaw affects VMware NSX-V Edge 6.2.x and 6.3.x running on any platform. Patches are included in versions 6.2.8 and 6.3.3.

Adi Sosnovich, Orna Grumberg and Gabi Nakibly have been credited for reporting the vulnerability.

Cisco has also published an advisory for this vulnerability and, in addition to applying the updates, advised administrators to allow only trusted users to access local systems, and monitor affected systems.

Last month, at the Black Hat security conference in Las Vegas, researchers showed how attackers with limited vSphere accounts could abuse a VMware API to access the guest operating system without authentication.

VMware has not released any patches, but it has shared some advice on how potential attacks can be prevented.

Related: VMware Patches Flaws in Horizon, vSphere Products

Related: VMware Patches Critical RCE Flaw in vCenter Server

Related: VMware Patches Vulnerabilities in AirWatch Android Apps

Related: VMware Patches Workstation Vulnerabilities

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.