Cisco IOS and IOS XE Software Secure Shell Connection on VRF Vulnerability

Vulnerability Description

A vulnerability in the access control logic of the Secure Shell (SSH) server of Cisco IOS and IOS XE Software may allow connections sourced from a virtual routing and forwarding (VRF) instance despite the absence of the vrf-also keyword in the access-class configuration. The vulnerability is due to a missing check in the SSH server. An attacker could use this vulnerability to open an SSH connection to an affected Cisco IOS or IOS XE device with a source address belonging to a VRF instance. Once connected, the attacker would still need to provide valid credentials to access the device.

References

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190109-ios-ssh-vrf
• http://www.securityfocus.com/bid/106560