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The U.S. Department of Energy
Computer Incident Advisory Center
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INFORMATION BULLETIN
Cisco web interface vulnerabilities in ACS for Windows
April 4, 2002 20:00 GMT Number M-064
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PROBLEM: 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.
PLATFORM: Cisco Secure Access Control Server for Windows version 2.6.x
and ACS 3.0.1 (build 40)
DAMAGE: By exploiting the format vulnerability an attacker may execute
the arbitrary code on the machine. This code will be executed
in the same context as Administrator. Executing arbitrary code
will lead to a total compromise of the machine. By exploiting
the directory traversal vulnerability an attacker can gain an
unauthorized access to information in one of the following file
types: html, htm, class, jpg, jpeg, or gif.
SOLUTION: Apply Cisco's security patch as directed in bulletin.
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VULNERABILITY The risk is HIGH. The execution of arbitrary code will lead to
ASSESSMENT: a total compromise of the machine.
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LINKS:
CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/M064.shtml
PATCHES: http://www.cisco.com/cgi-bin/tablebuild.pl/cs-acs-win
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[****** Start Cisco Systems Advisory ******]
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. 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
http://www.cisco.com/warp/public/707/ACS-Win-Web.shtml.
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. This technique is
described in the following article:
http://www.securityfocus.com/archive/1/66842.
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 hardcoded
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. 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.
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 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/.
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.
Exploitation and Public Announcements
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.
Status of This Notice: FINAL
This is a final notice. Although Cisco cannot guarantee the accuracy of
all statements in this notice, all of the facts have been checked to the
best of our ability. Cisco does not anticipate issuing updated versions
of this notice unless there is some material change in the facts. Should
there be a significant change in the facts, Cisco may update this notice.
A standalone copy or paraphrase of the text of this security advisory that
omits the distribution URL in the following section is an uncontrolled
copy, and may lack important information or contain factual errors.
Distribution
This notice will be posted on Cisco's Worldwide Web site at
http://www.cisco.com/warp/public/707/ACS-Win-Web.shtml. 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:
cust-security-announce@cisco.com
bugtraq@securityfocus.com
first-teams@first.org (includes CERT/CC)
cisco@spot.colorado.edu
comp.dcom.sys.cisco
firewalls@lists.gnac.com
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 givenabove for any updates.
Revision History
Revision Number
1.0
2002-April-03 16:00 UTC
+0000
Initial Public Release
Cisco Security Procedures
Complete information on reporting security vulnerabilities in Cisco
products, obtaining assistance with security incidents, and registering
to receive security information from Cisco, is available on Cisco's
Worldwide Web site at
http://www.cisco.com/warp/public/707/sec_incident_response.shtml.
This includes instructions for press inquiries regarding Cisco security
notices.
All Cisco Security Advisories are available at
http://www.cisco.com/go/psirt.
This notice is Copyright 2002 by Cisco Systems, Inc. This notice may be
redistributed freely after the release date given at the top of the text,
provided that redistributed copies are complete and unmodified, and include
all date and version information.
[****** End Cisco Systems Advisory ******]
_____________________________________________________________________________
CIAC wishes to acknowledge the contributions of Cisco for the
information contained in this bulletin.
_______________________________________________________________________________
CIAC, the Computer Incident Advisory Center, is the computer
security incident response team for the U.S. Department of Energy
(DOE) and the emergency backup response team for the National
Institutes of Health (NIH). CIAC is located at the Lawrence Livermore
National Laboratory in Livermore, California. CIAC is also a founding
member of FIRST, the Forum of Incident Response and Security Teams, a
global organization established to foster cooperation and coordination
among computer security teams worldwide.
CIAC services are available to DOE, DOE contractors, and the NIH. CIAC
can be contacted at:
Voice: +1 925-422-8193 (7x24)
FAX: +1 925-423-8002
STU-III: +1 925-423-2604
E-mail: ciac@ciac.org
Previous CIAC notices, anti-virus software, and other information are
available from the CIAC Computer Security Archive.
World Wide Web: http://www.ciac.org/
Anonymous FTP: ftp.ciac.org
PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing
communities receive CIAC bulletins. If you are not part of these
communities, please contact your agency's response team to report
incidents. Your agency's team will coordinate with CIAC. The Forum of
Incident Response and Security Teams (FIRST) is a world-wide
organization. A list of FIRST member organizations and their
constituencies can be obtained via WWW at http://www.first.org/.
This document was prepared as an account of work sponsored by an
agency of the United States Government. Neither the United States
Government nor the University of California nor any of their
employees, makes any warranty, express or implied, or assumes any
legal liability or responsibility for the accuracy, completeness, or
usefulness of any information, apparatus, product, or process
disclosed, or represents that its use would not infringe privately
owned rights. Reference herein to any specific commercial products,
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otherwise, does not necessarily constitute or imply its endorsement,
recommendation or favoring by the United States Government or the
University of California. The views and opinions of authors expressed
herein do not necessarily state or reflect those of the United States
Government or the University of California, and shall not be used for
advertising or product endorsement purposes.
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