Cisco Security Advisory-
In CiscoSecure Access Control Server (CiscoSecure ACS) for UNIX, versions 1.0 through 2.3.2, there is a database access protocol that could permit unauthorized remote users to read and write the server database without authentication. Depending on the network environment, this might permit unauthorized users to modify the access policies enforced by the CiscoSecure ACS. A utility that is capable of using this protocol to read or modify a database is shipped with the CiscoSecure ACS product.
This vulnerability can be eliminated by either a CiscoSecure configuration change, or network configuration change. Cisco has provided a new release that changed a default setting, in order to ensure higher default security level.
This vulnerability has Cisco bug ID CSCdm71489.
This advisory is posted at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-19990819-dbaccess.
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This section provides details on affected products.
Vulnerable Products
If you are running an affected version of CiscoSecure ACS for UNIX, and if you have not modified the configuration to strictly permit connections from trusted hosts, and if untrusted users can make TCP connections to TCP port 9900 on the computer on which you have installed CiscoSecure ACS, then you are vulnerable.
Products Confirmed Not Vulnerable
Users of CiscoSecure ACS for Windows NT are not vulnerable.
No other Cisco products are currently known to be affected by these vulnerabilities.
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This vulnerability has been assigned Cisco bug ID CSCdm71489.
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Two workarounds for this vulnerability exist.
One workaround consists of enabling client validation within CiscoSecure ACS for UNIX. A caveat to this workaround is that there are some versions of CiscoSecure ACS for UNIX that are subject to another defect, which prevents access to additional administration utilities (the Advanced Administration GUI) within CiscoSecure ACS for UNIX when the client validation feature is enabled. This problem is identified in CSCdm72555 which affects versions 2.3.1 and 2.3.2, and CSCdk55423, which affects versions 2.2.2, 2.2.3 of CiscoSecure ACS for UNIX. This workaround will not be effective in CiscoSecure ACS for UNIX version 2.2.2, 2.2.3, 2.3.1 and 2.3.2, and customers are encouraged to upgrade to a version that does not include this defect. Version 2.3.3 is currently available and is not susceptible to the above problem.
You must edit the CSCconfig.ini file, list the permitted remote access hosts, enable remote client validation. TACACS or RADIUS clients do NOT need to be listed under this setting, only hosts that are permitted to administer the server should be listed.
In the following example, 'acs_srv_machine' resolves to localhost, and we are providing remote administration privileges to the hosts 'client_machine' and the ip address 172.16.23.23. Permitted clients may be defined by a hostname, or an ip address.
CSCconfig.ini file should be edited with the following information:
[ValidClients] ;if ValidateClients=true, than we only allow the clients with ids listed ; to connect to the dbserver 100 = acs_srv_machine 100 = client_machine 100 = 172.16.23.23 ValidateClients = true ...
An additional configuration parameter "FastAdminValidClients" was added in CiscoSecure ACS version 2.3.3 allowing the Fast Administrator Web based GUI to permit the same IP addresses specified in the valid clients list, to further restrict client access.
A second workaround is to use filtering on other network devices, such as a firewall, to control or block access to TCP port 9900 on the CiscoSecure ACS for UNIX server.
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This applies ONLY to CiscoSecure ACS for UNIX, and is present in all versions, up to version 2.3.2. Version 2.3.3 of CiscoSecure ACS for UNIX has been modified to validate administrative clients by default.
This vulnerability applies only to the software product CiscoSecure Access Control Server for UNIX, and does not apply to CiscoSecure Access Control Server for NT.
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Cisco does not have any reports of malicious use of this vulnerability. CiscoSecure ACS for UNIX Reference Guide does include a cautionary note regarding this vulnerability.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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