Flexible Enforcement of Multi-factor Authentication with SSH via Linux-PAM for Federated Identity Users
Derek Simmel, Shane Filus · 2017
A computational science project with restricted-access data was awarded an allocation by XSEDE in 2016 to use the Bridges supercomputer at the Pittsburgh Supercomputing Center (PSC). As a condition of the license agreement for access to the data, multi-factor authentication (MFA) with XSEDE's Duo MFA service is required for users of this project to login to Bridges via SSH, in addition to filesystem access controls. Since not all Bridges users are required to authenticate to Bridges in this manner, a solution was implemented via Linux-PAM to require XSEDE Duo MFA for SSH login access by specific users, as identified by their local account name or membership in a local group. This paper describes the implementation on Bridges and its extensibility to other systems and environments with similar needs.