CVE-2020-3398 Cisco NX-OS Software Border Gateway Protocol Multicast VPN Session Denial of Service Vulnerability
Remote attackers can cause BGP session resets and partial denial of service by sending malformed MVPN update messages to Cisco NX-OS devices.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2020-3398?
CVE-2020-3398 is a high-severity denial of service vulnerability in Cisco Nx-Os, published on 27 Aug 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability in the Border Gateway Protocol (BGP) Multicast VPN (MVPN) implementation of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a BGP session to repeatedly reset, causing a partial denial of service (DoS) condition due to the BGP session being down. The vulnerability is due to incorrect parsing of a specific type of BGP MVPN update message. An attacker could exploit this vulnerability by sending this BGP MVPN update message to a targeted device. A successful exploit could allow the attacker to cause the BGP peer connections to reset, which could lead to BGP route instability and impact traffic. The incoming BGP MVPN update message is valid but is parsed incorrectly by the NX-OS device, which could send a corrupted BGP update to the configured BGP peer. Note: The Cisco implementation of BGP accepts incoming BGP traffic from only explicitly configured peers. To exploit this vulnerability, an attacker must send a specific BGP MVPN update message over an established TCP connection that appears to come from a trusted BGP peer. To do so, the attacker must obtain information about the BGP peers in the trusted network of the affected system.
Weakness: CWE-20
Which versions are affected by CVE-2020-3398?
It affects 1 product.
Products include Cisco Nx-Os.
How do I fix CVE-2020-3398?
No fix has been published for CVE-2020-3398 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2020-3398 being exploited?
There is no known exploitation of CVE-2020-3398 in the wild and no public exploit code.
Other vulnerabilities in Cisco Nx-Os
Sources
Also known as GHSA-4jqq-x95h-w7jm.