Title: OWA Function Allows Unauthenticated User to Enumerate Global Address List
Date: 06 September 2001
Software: Exchange 5.5
Impact: Information Disclosure
Affected or interested? Read More... Issue: Among the functions Outlook Web Access (OWA) in Exchange 5.5 offers is the ability to search the global address list (GAL). By design, this is an authenticated function, implemented as a two-tier architecture - a front tier that provides a user interface and a back-end tier that actually performs the search. However, only the front tier actually checks authentication. An attacker who sent a properly formatted request to the back-end function that actually performs the search could enumerate the GAL without authenticating. Mitigating Factors: - The vulnerability would only allow the attacker to learn users' email aliases. It would not provide any other capabilities. Specifically, it would not give the attacker any way to create or send mail as a user; to read, change or delete mail; or to perform any other functions on the server. - The vulnerability is only exploitable via OWA. Exchange servers that are not configured to offer OWA are not affected by the vulnerability. - The vulnerability does not affect Exchange 2000, even when offering OWA. Patch Availability: A patch is available to fix this vulnerability. Please read the Security Bulletin at M$ Security Bulletin MS01-47 for information on obtaining this patch.
Date: 06 September 2001
Software: Exchange 5.5
Impact: Information Disclosure
Affected or interested? Read More... Issue: Among the functions Outlook Web Access (OWA) in Exchange 5.5 offers is the ability to search the global address list (GAL). By design, this is an authenticated function, implemented as a two-tier architecture - a front tier that provides a user interface and a back-end tier that actually performs the search. However, only the front tier actually checks authentication. An attacker who sent a properly formatted request to the back-end function that actually performs the search could enumerate the GAL without authenticating. Mitigating Factors: - The vulnerability would only allow the attacker to learn users' email aliases. It would not provide any other capabilities. Specifically, it would not give the attacker any way to create or send mail as a user; to read, change or delete mail; or to perform any other functions on the server. - The vulnerability is only exploitable via OWA. Exchange servers that are not configured to offer OWA are not affected by the vulnerability. - The vulnerability does not affect Exchange 2000, even when offering OWA. Patch Availability: A patch is available to fix this vulnerability. Please read the Security Bulletin at M$ Security Bulletin MS01-47 for information on obtaining this patch.
