An improper authentication vulnerability can be exploited through a race condition that occurs in Ellucian Banner Web Tailor 8.8.3, 8.8.4, and 8.9 and Banner Enterprise Identity Services 8.3, 8.3.1, 8.3.2, and 8.4, in conjunction with SSO Manager. This vulnerability allows remote attackers to steal a victim's session (and cause a denial of service) by repeatedly requesting the initial Banner Web Tailor main page with the IDMSESSID cookie set to the victim's UDCID, which in the case tested is the institutional ID. During a login attempt by a victim, the attacker can leverage the race condition and will be issued the SESSID that was meant for this victim.