CVE-2017-3804

Vulnerability

A vulnerability in Intermediate System-to-Intermediate System (IS-IS) protocol packet processing of Cisco Nexus 5000, 6000, and 7000 Series Switches software could allow an unauthenticated, adjacent attacker to cause a reload of the affected device. The issue is due to improper processing of crafted IS-IS protocol packets. Switches in the FabricPath domain crash because of an __inst_001__isis_fabricpath hap reset when processing a crafted link-state packet. Affected releases include versions 7.1(3)N1(2.1), 7.1(3)N1(3.12), 7.3(2)N1(0.296), and 8.0(1)S2 [1].

Exploitation

An attacker must be adjacent to the target switch and able to send crafted IS-IS protocol packets over an established adjacency. No authentication is required. The attacker sends a specially crafted link-state packet, which triggers a reset due to improper packet processing, leading to a device reload [1].

Impact

Successful exploitation results in a denial of service (DoS) condition via an unplanned reload of the affected switch. The device becomes temporarily unavailable, disrupting network operations. There is no information disclosure or remote code execution [1].

Mitigation

Fixed software releases are available, including 6.2(18)S11, 7.0(3)I5(1.170), 7.0(3)I5(2), 7.1(4)N1(0.4), 7.1(4)N1(1b), 7.1(5)N1(0.986), 7.1(5)N1(1), 7.2(3)D1(0.8), 7.3(2)N1(0.304), 7.3(2)N1(1), 8.0(0.96)S0, 8.0(1), 8.0(1)E1, 8.0(1)S4, and 8.3(0)CV(0.788). No workarounds exist [1].