A vulnerability in the SSH management interface of the Cisco Unified Computing System (UCS) 6200 Series Fabric Interconnect Series Switch could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition because a fabric interconnect interface might not boot completely up or might have high CPU utilization. This would only happen if the attack occurred while a reload of the affected UCS switch was already in progress.
The vulnerability is due to a lack of rate-limiting on incoming TCP connection requests for SSH, which is TCP port 22 during boot time. An attacker could exploit this vulnerability by sending a TCP SYN flood of packets to the SSH management interface of the device while a reload of the switch is in progress. An exploit could allow the attacker to create a DoS condition due to the Cisco UCS FI not proper properly booting up or having high CPU utilization.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
This advisory is available at the following link: http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151210-ucs