Advisory ID: cisco-sa-20020207-acs-nds-auth
For Public Release 2002 Februrary 7 16:00 UTC (GMT)
Specific versions of Cisco Secure Authentication Control Server (ACS)
allows authentication of users that have been explicitly disabled or expired in
the Novell Directory Services (NDS). There is a software patch that may be
applied, and software upgrades will also address this problem.
The complete notice will be available at
This section provides details on affected products.
Only Cisco Secure ACS version 3.0.1, configured for NDS, is affected.
The following are NOT affected by this vulnerability:
Systems with Cisco Secure ACS for Windows NT version 2.6 and 2.5 and
Cisco Secure ACS version 3.0.1 that is NOT configured for use with
Cisco Secure ACS for UNIX
No other Cisco products are currently known to be affected by these
To determine if your Cisco Secure ACS for Windows NT server is
configured for NDS, please review the "External User Databases/Unknown User
Policy" on the Administration interface. If the name of your NDS configuration
appears in the "Selected Databases" list, then you are using NDS for
authentication and are affected by this vulnerability if you are running
Users who are marked as "expired" or "disabled" on the NDS database
will still authenticate if their credentials are otherwise correct. The file
"NDSAuth.DLL" is a module which allows ACS authentication to be handled by an
external NDS server. Versions of this file with the date 2001-Dec-15 ignore the
"Disabled" or "Expired" state of these users on NDS. Authentication attempts by
users with a Disabled or Expired status on the NDS server should be refused,
but are permitted due to this vulnerability.
This vulnerability is documented in Cisco Bug ID CSCdw46931.
CSCdw46931 -- DEL/ACS authenticates NDS
Cisco has provided scores for the vulnerabilities in this advisory based on the Common Vulnerability Scoring System (CVSS). The CVSS scoring in this Security Advisory is done in accordance with CVSS version 2.0.
CVSS is a standards-based scoring method that conveys vulnerability severity and helps determine urgency and priority of response.
Cisco has provided a base and temporal score. Customers can then compute environmental scores to assist in determining the impact of the vulnerability in individual networks.
Cisco has provided an FAQ to answer additional questions regarding CVSS at
Cisco has also provided a CVSS calculator to help compute the environmental impact for individual networks at
This vulnerability results in a failure to adequately enforce
authentication criteria, and users that should be prevented from using services
are permitted to authenticate, regardless of their status in the NDS server.
CiscoSecure ACS for Windows NT Server version 3.0.1 is vulnerable and
can be patched. Future versions of the software will include this patch. Please
review the Workarounds section of this
notice for detailed patch installation instructions.
The patch for this vulnerability can be downloaded from the following
location if you are logged in with a valid CCO user account:
If you are unable to install the patch, user records that are
"disabled" or "expired" in your NDS database should be temporarily removed
until they are either valid again or the patch has been installed.
Install the patch according to the following directions:
Stop both "CSAUTH" and "CSAdmin" services by entering the following
at the command prompt:
net stop CSAuth
net stop CSAdmin
Locate the <CSNTinstall>/Authenticators directory. For a
default installation on the C:\ drive, the location will be the following:
C:\Program Files\CiscoSecure ACS v3.0\Authenticators\NDSAuth.dll.
Rename the original NDSAuth.dll to something else (NDSAuth_old.dll,
for example) to save it.
Replace the original NDSAuth.dll file with the patch file in its
Restart the services by entering the following at the command
net start CSAuth
net start CSAdmin
The patch is a single file and can be downloaded at the following
location if you are logged in with a valid CCO user account:
Cisco has made free software available to address this vulnerability
for affected customers. Prior to deploying software, customers should consult
their maintenance provider or check the software for feature set compatibility
and known issues specific to their environment.
Customers may only install and expect support for the feature sets they
have purchased. By installing, downloading, accessing or otherwise using such
software upgrades, customers agree to be bound by the terms of Cisco's software
license terms found at
or as otherwise set forth at Cisco.com Downloads at
Do not contact either "email@example.com" or "firstname.lastname@example.org"
for software upgrades.
Customers with contracts should obtain upgraded software through their
regular update channels. For most customers, this means that upgrades should be
obtained through the Software Center on Cisco's worldwide website at
Customers whose Cisco products are provided or maintained through prior
or existing agreement with third-party support organizations such as Cisco
Partners, authorized resellers, or service providers should contact that
support organization for guidance and assistance with the appropriate course of
action in regards to this advisory.
The effectiveness of any workaround or fix is dependent on specific
customer situations such as product mix, network topology, traffic behavior,
and organizational mission. Due to the variety of affected products and
releases, customers should consult with their service provider or support
organization to ensure any applied workaround or fix is the most appropriate
for use in the intended network before it is deployed.
Customers who purchase direct from Cisco but who do not hold a Cisco
service contract and customers who purchase through third-party vendors but are
unsuccessful at obtaining fixed software through their point of sale should get
their upgrades by contacting the Cisco Technical Assistance Center (TAC). TAC
contacts are as follows.
+1 800 553 2447 (toll free from within North America)
+1 408 526 7209 (toll call from anywhere in the world)
Have your product serial number available and give the URL of this
notice as evidence of your entitlement to a free upgrade. Free upgrades for
non-contract customers must be requested through the TAC.
for additional TAC contact information, including special localized telephone
numbers and instructions and e-mail addresses for use in various
This vulnerability was discovered by internal Quality Assurance.
The Cisco PSIRT is not aware of any public announcements or malicious
use of the vulnerability described in this advisory.
THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
A stand-alone copy or Paraphrase of the text of this document that omits the distribution URL in the following section is an uncontrolled copy, and may lack important information or contain factual errors.
This notice will be posted on Cisco's worldwide website at
In addition to Worldwide Web posting, a text version of this notice is
clear-signed with the Cisco PSIRT PGP key and is posted to the following e-mail
and Usenet news recipients:
email@example.com (includes CERT/CC)
Various internal Cisco mailing lists
Future updates of this notice, if any, will be placed on Cisco's
Worldwide Web server, but may or may not be actively announced on mailing lists
or newsgroups. Users concerned about this problem are encouraged to check the
URL given above for any updates.
Initial public release.