[NT] Cisco Secure ACS Web Server Found to Contain Vulnerabilities

From: support@securiteam.com
Date: 04/04/02


From: support@securiteam.com
To: list@securiteam.com
Date: Thu,  4 Apr 2002 10:46:34 +0200 (CEST)

The following security advisory is sent to the securiteam mailing list, and can be found at the SecuriTeam web site: http://www.securiteam.com
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  Cisco Secure ACS Web Server Found to Contain Vulnerabilities
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SUMMARY

Cisco Secure Access Control Server (ACS) for Windows contains two
vulnerabilities. One vulnerability can lead to the execution of an
arbitrary code on an ACS server and the second can lead to an unauthorized
disclosure of information. The patch is available for both
vulnerabilities.

Cisco Secure ACS for UNIX is not vulnerable. No other Cisco product is
vulnerable.

There is no direct workaround for the vulnerabilities but it is possible
to mitigate them largely. See the Workarounds section for details.

DETAILS

Affected Products:
The affected product is Cisco Secure Access Control Server for Windows
releases 2.6.x and ACS 3.0.1 (build 40). A patch is available.

Cisco Secure ACS for UNIX is not affected.

No other Cisco products are affected.

Details:
There are two different vulnerabilities, as described by the Bug IDs
below. The first can lead to execution of an arbitrary code; the second
can be used to reveal customer data.

Bug IDs CSCdx17622 and CSCdx17683
By connecting to port 2002 and sending a crafted URL, it is possible to,
in a less severe case, kill the CSADMIN module or, in a severe case, to
execute an arbitrary user-supplied code. The functionality of
authentication, authorization, and accounting (AAA) is not affected by
termination of the CSADMIN module. This means that users will be able to
authenticate normally. Only the administration function will be affected.
Port 2002 is used by the CSADMIN module for remote administration.

By providing a URL containing formatting symbols (for example, %s, %p), it
is possible to execute a user-provided code.

Bug IDs CSCdx17689 and CSCdx17698
By using "..\.." in the URL it is possible to access data in any directory
outside the Web root directory but on the same hard disk or disk
partition. With this technique, it is possible to access only the
following file types: html, htm, class, jpg, jpeg, or gif.

Please note that an attacker must know the exact location and file name.
It is not possible to browse a directory this way.

Impact:
By exploiting the format vulnerability, an attacker may execute arbitrary
code on the machine. This code will be executed in the same context as the
CSADMIN process, and that is as administrator. Executing arbitrary code
will lead to a total compromise of the machine.

By exploiting the directory traversal vulnerability, an attacker can gain
unauthorized access to information in the following file types: html, htm,
class, jpg, jpeg, or gif. The main issue may be html files with hard coded
passwords or other sensitive information.

Software Versions and Fixes:
Both vulnerabilities are fixed by the patched CSAdmin.exe files available
at <http://www.cisco.com/cgi-bin/tablebuild.pl/cs-acs-win>
http://www.cisco.com/cgi-bin/tablebuild.pl/cs-acs-win. The file names are
CSAdmin-patch-2.6-4-4.zip and CSAdmin-patch-3.0-1-40.zip.

Note: To download these patches, you must be a registered user and you
must be logged in. Unregistered users should refer to the instructions in
the Obtaining Fixed Software section.

To install the patch, follow the procedure below while logged in as
Administrator.
1) Manually stop the CSAdmin service.
2) Rename the <ACS-DIR>/CSAdmin/CSAdmin.exe file
3) Copy the patched CSAdmin.exe to <ACS-DIR>/CSAdmin.
4) Manually start the CSAdmin service.

Obtaining Fixed Software:
Cisco is offering a free software patch to address this vulnerability for
all affected customers. Customers may only install and expect support for
the feature sets they have purchased.

Customers with service contracts should contact their regular update
channels to obtain any software release containing the feature sets they
have purchased. For most customers with service contracts, this means that
upgrades should be obtained through the Software Center on Cisco's
Worldwide Web site at <http://www.cisco.com> http://www.cisco.com.

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 assistance with the upgrade.

Customers who purchased directly 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 obtain fixed software by contacting the Cisco Technical
Assistance Center (TAC). In these cases, customers may only upgrade to a
later version of the same release.

Cisco 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)
 * e-mail: tac@cisco.com

See <http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml>
http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml for additional
TAC contact information, including special localized telephone numbers and
instructions and e-mail addresses for use in various languages.

Please have your product serial number available and give the URL of this
notice as evidence of your entitlement to a free upgrade.

Please do not contact either "psirt@cisco.com" or
"security-alert@cisco.com" for software upgrades.

Workarounds:
There are no direct workarounds for these vulnerabilities. However, by
exercising the standard best practices, it is possible to significantly
mitigate both issues. These practices are:

 * Block all unnecessary traffic on the outer network edge. This includes
private IP address space (10.0.0.0, for example) and spoofed packets. This
can be accomplished using routers or firewalls. For instruction on how to
accomplish this with Cisco routers, please consult documents at
<http://www.cisco.com/public/cons/isp/>
http://www.cisco.com/public/cons/isp/.

 * Separate critical internal infrastructure from the rest of your
internal network.

We strongly recommend that these practices are also followed when
deploying Cisco ACS for Unix, even though it is not vulnerable to the
mentioned issues.

ADDITIONAL INFORMATION

The information has been provided by <mailto:psirt@cisco.com> Cisco
Systems Product Security Incident Response Team.

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