Published:
07 February 2002
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-----BEGIN PGP SIGNED MESSAGE----- =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2002.063 -- Microsoft Security Bulletin MS02-003 Exchange 2000 System Attendant Incorrectly Sets Remote Registry Permissions 8 February 2002 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Microsoft Exchange System Attendant Vendor: Microsoft Impact: Access Privileged Data Access Required: Remote - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- - - ---------------------------------------------------------------------- Title: Exchange 2000 System Attendant Incorrectly Sets Remote Registry Permissions Date: February 07, 2002 Software: Exchange Server 2000 Impact: Less Secure Default Settings Max Risk: Low Bulletin: MS02-003 Microsoft encourages customers to review the Security Bulletin at: http://www.microsoft.com/technet/security/bulletin/MS02-003.asp. - - ---------------------------------------------------------------------- Issue: ====== The Microsoft Exchange System Attendant is one of the core services in Microsoft Exchange. It performs a variety of functions related to the on-going maintenance of the Exchange system. To allow remote administration of an Exchange Server using the Exchange System Manager Microsoft Management Console (MMC) snap in, the System Attendant makes changes to the permissions on the Windows Registry to allow Exchange Administrators to remotely update configuration settings stored in the Registry. There is a flaw in how the System Attendant makes these Registry configuration changes. This flaw could allow an unprivileged user to remotely access configuration information on the server. Specifically, this flaw inappropriately gives the "Everyone" group privileges to the WinReg key. This key controls the ability of users and groups to remotely connect to the Registry. By default, only Administrators are given the ability to remotely connect to the Registry, by granting permissions on this key. The flaw does not grant any abilities beyond the ability to connect remotely. However, an attacker's ability to make changes to the Registry once they have successfully connected would be dictated by the permissions on the specific keys within the Registry itself. Thus, while this vulnerability does not itself give an attacker the ability to change Registry settings, it could be used in conjunction with inappropriately permissive registry settings to gain access to, and make changes to a systems Registry. Mitigating Factors: ==================== - The vulnerability only grants the ability to connect to the Registry remotely. It does not weaken any other permissions in the Registry. - An attacker's ability to connect to the Registry remotely requires the ability to send SMB traffic to and from the target system. Firewalling best practices recommends closing the ports that NetBIOS and Direct Host uses (tcp ports 139 and 445) Risk Rating: ============ - Internet systems: Low - Intranet systems: Low - Client systems: None Patch Availability: =================== - A patch is available to fix this vulnerability. Please read the Security Bulletin at http://www.microsoft.com/technet/security/bulletin/ms02-003.asp for information on obtaining this patch. Acknowledgment: =============== - Eitan Caspi (EITANC@YAHOO.COM) - - --------------------------------------------------------------------- THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 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Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/Information/advisories.html If you believe that your system has been compromised, contact AusCERT or your representative in FIRST (Forum of Incident Response and Security Teams). Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for emergencies. -----BEGIN PGP SIGNATURE----- Version: 2.6.3i Charset: noconv Comment: ftp://ftp.auscert.org.au/pub/auscert/AUSCERT_PGP.key iQCVAwUBPGP4xyh9+71yA2DNAQG9ggP8CIOtfxFYlIi6nmJEDWXTpILzvzcqwwqR dsyGF0Fxzbnb+29WXUkiZ+3anz3puikEHa4nC4AXatcylIkZdVO+QpzH9EOcQRCU BpxP6oUenjy7PaIwBtOudfPEEaC+Vjn83D/nSQTXiYOmr5jKSvHgcGSbtJBVBEyI /NnBeVa/T1o= =rZtW -----END PGP SIGNATURE-----