Cisco Security Advisory-
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. A 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 to a great extent. See the Workarounds section for details.
This advisory is available at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20020403-acs-win-web.
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This section provides details on affected products.
Vulnerable Products
The affected product is Cisco Secure Access Control Server for Windows; all releases up to and including 2.6.x and ACS 3.0.1 (build 40) are affected.
Products Confirmed Not Vulnerable
Cisco Secure ACS for Unix is not affected.
No other Cisco products are currently known to be affected by these vulnerabilities.
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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.
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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. This technique is described in the following article: http://www.securityfocus.com/archive/1/66842
.
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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.
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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.
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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:
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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/en/US/tech/tk648/tk361/technologies_white_paper09186a00801afc76.shtml.
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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.
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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/en/US/tech/tk648/tk361/technologies_white_paper09186a00801afc76.shtml.
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Both vulnerabilities are fixed by the patched CSAdmin.exe files available at http://www.cisco.com/pcgi-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. These patches must be applied only to releases 2.6(4.4) and 3.0.1 (build 40). If you are running any other release, you should open a case with the Cisco Technical Assistance Center (TAC) to receive a free upgrade. After upgrading to release 2.6(4.4) or 3.0.1 (build 40), you should apply the patches.
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.
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Manually stop the CSAdmin service.
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Rename the <ACS-DIR>/CSAdmin/CSAdmin.exe file
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Copy the patched CSAdmin.exe to <ACS-DIR>/CSAdmin.
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Manually start the CSAdmin service.
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Manually stop the CSAdmin service.
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Both vulnerabilities were reported by Jonas Ländin and Patrik Karlsson from iXsecurity. Cisco PSIRT was made aware that an exploit program for the format vulnerability exists. This exploit is not thought to be released to the general public.
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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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Revision 1.1
2002-April-05
Updates made to Affected Products, and Software Versions and Fixes.
Revision 1.0
2002-April-03
Initial Public Release
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