Advisory ID: cisco-sa-20070105-csacs
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20070105-csacs
Revision 1.0
For Public Release 2007 January 5 16:00 UTC (GMT)
Contents
Summary
Affected Products
Details
Vulnerability Scoring Details
Impact
Software Versions and Fixes
Workarounds
Obtaining Fixed Software
Exploitation and Public Announcements
Status of This Notice: Final
Distribution
Revision History
Cisco Security Procedures
Summary
Certain versions of Cisco Secure Access Control Server (ACS) for Windows and the Cisco Secure ACS Solution Engine (here after both referred to as purely Cisco Secure ACS) are affected by multiple vulnerabilities that cause specific Cisco Secure services to crash. Two of the vulnerabilities may permit arbitrary code execution after exploitation of the specified vulnerability.
Affected Cisco Secure ACS services, and the impact of the vulnerabilities are as follows:
-
Specially Crafted HTTP GET Request Vulnerability:
Processing a specially crafted HTTP GET request may crash the CSAdmin service. This vulnerability is also susceptible to a stack overflow condition. -
Specially Crafted RADIUS Accounting-Request Vulnerability:
Processing a specially crafted RADIUS Accounting-Request packet may crash the CSRadius service. This vulnerability is also susceptible to a stack overflow condition. -
Specially Crafted RADIUS Access-Request Vulnerabilities:
Processing a specially crafted RADIUS Access-Request packet may crash the CSRadius service.
We would like to thank CESG's Vulnerability Research Group and National Infrastructure Security Co-ordination Centre (NISCC) for reporting several of these vulnerabilities to Cisco Systems.
We greatly appreciate the opportunity to work with researchers on security vulnerabilities, and welcome the opportunity to review and assist in product reports.
Cisco has released free software updates that address these vulnerabilities. Workarounds that mitigate these vulnerabilities are available. This advisory is posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20070105-csacs.Affected Products
Vulnerable Products
The following products are vulnerable to one or more of the vulnerabilities, when running software versions prior to 4.1:
- Cisco Secure Access Control Server for Windows
- Cisco Secure Access Control Server Solution Engine
To determine if you are running a vulnerable version of Cisco Secure ACS, first log into the Web administrative session for Cisco Secure ACS and on the home page at the bottom section of the screen will be the release information. The following example would be seen when running Cisco Secure ACS software version 4.0(1) Build 27:
CiscoSecure ACS ACS software version 4.0(1) Build 27: Copyright information is seen underneath this information.
Products Confirmed Not Vulnerable
- Cisco Secure ACS for Unix (CSU).
- Cisco CNS Access Registrar (CAR).
- Cisco Secure ACS server for Windows version 4.1(X) or later.
- Cisco Secure ACS server solution Engine version 4.1(X) or later.
Details
Cisco Secure ACS is a scalable, high-performance Remote Access Dial-In User Service (RADIUS) and Terminal Access Controller Access Control System Plus (TACACS+) security server.
Multiple vulnerabilities exist in certain versions of the Cisco Secure ACS that may cause the services CSAdmin or CSRadius to crash.
CSAdmin is the service that provides the web server for the ACS web administration interface.
CSRadius is the service that communicates between the CSAuth module (the authentication and authorization service) and the access device that is requesting authentication and authorization services.
Specially Crafted HTTP GET Request Vulnerability
This vulnerability is exploited by processing a specially crafted HTTP GET request. Upon successful exploitation, the CSAdmin service may crash. This vulnerability is also susceptible to a stack based overflow condition which may allow arbitrary code execution if successfully exploited.
If this vulnerability is successfully exploited, the CSAdmin service will require a manual restart of the service. Normal Authentication, Authorization and Accounting (AAA) processing will continue.
While CSAdmin is in the stopped state, users cannot access the Cisco Secure ACS administrative interface from any computer other than the Windows server or appliance on which it is running. With Cisco Secure ACS for Windows you can start or stop CSAdmin from the Windows Control Panel. With Cisco Secure ACS Solution Engine, you can restart the service by using only the appliance serial console.
For further details on starting the CSAdmin service please refer to: http://www.cisco.com/en/US/docs/net_mgmt/cisco_secure_access_control_server_for_windows/4.1/user/A_Arch.html#wp7264
This vulnerability is documented in Cisco Bug ID:
- CSCsd96293 ( registered customers only) -- Stack based overflow within CSAdmin when processing HTTP GET request
Specially Crafted RADIUS Accounting-Request Vulnerability
This vulnerability is exploited by processing a specially crafted RADIUS Accounting-Request packet. Upon successful exploitation, the CSRadius service may crash and an exception trap error will be generated for the CSRadius service within the Windows Event Viewer System log. This vulnerability is also susceptible to a stack based overflow condition which may allow arbitrary code execution if successfully exploited.
The RADIUS secret key that is shared between the Network Access Server (NAS) and the Cisco Secure ACS server and/or appliance is required to exploit this vulnerability.
This vulnerability is documented in Cisco Bug ID:
- CSCse18278 ( registered customers only) -- Stack based overflow within CSRadius when processing Accounting-Request. (CVE-2006-4098)
Specially Crafted RADIUS Access-Request Vulnerabilities
Several vulnerabilities exist in Cisco Secure ACS that may cause the CSRadius service to crash when processing a specially crafted RADIUS Access-Request packet. These vulnerabilities will not allow arbitrary code execution after successful exploitation. An exception trap error will be recorded within the CSRadius log file and an error will be seen for the CSRadius service within the Windows Event Viewer System log after successful exploitation.
The RADIUS secret key that is shared between the Network Access Server (NAS) and the Cisco Secure ACS server and/or appliance is not required to exploit these vulnerabilities.
These vulnerabilities are documented in Cisco Bug IDs:
- CSCse18250 ( registered customers only) -- CSRadius Service crashes when processing a specially crafted Access-Request packet. (CVE-2006-4097)
- CSCeg04788 ( registered customers only) -- CSRadius Service crashes when processing a specially crafted Access-Request packet.
- CSCeg04666 ( registered customers only) -- CSRadius Service crashes when processing a specially crafted Access-Request packet.
Vulnerability Scoring Details
Cisco is providing scores for the vulnerabilities in this advisory based on the Common Vulnerability Scoring System (CVSS).
Cisco will provide a base and temporal score. Customers can then compute environmental scores to assist in determining the impact of the vulnerability in individual networks.
Cisco PSIRT will set the bias in all cases to normal. Customers are encouraged to apply the bias parameter when determining the environmental impact of a particular vulnerability.
CVSS is a standards based scoring method that conveys vulnerability severity and helps determine urgency and priority of response.
Cisco has provided an FAQ to answer additional questions regarding CVSS at http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html.
Cisco has also provided a CVSS calculator to help compute the environmental impact for individual networks at http://intellishield.cisco.com/security/alertmanager/cvss.
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CSCsd96293 ( registered customers only) - Stack based overflow within CSAdmin when processing HTTP GET request. |
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|---|---|---|---|---|---|---|
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CVSS Base Score - 10 |
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|
Access Vector |
Access Complexity |
Authentication |
Confidentiality Impact |
Integrity Impact |
Availability Impact |
Impact Bias |
|
Remote |
Low |
Not Required |
Complete |
Complete |
Complete |
Normal |
|
CVSS Temporal Score - 8.3 |
||||||
|
Exploitability |
Remediation Level |
Report Confidence |
||||
|
Functional |
Official Fix |
Confirmed |
||||
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CSCse18278 ( registered customers only) - Stack based overflow within CSRadius when processing Accounting-Request. |
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|---|---|---|---|---|---|---|
|
CVSS Base Score - 6.0 |
||||||
|
Access Vector |
Access Complexity |
Authentication |
Confidentiality Impact |
Integrity Impact |
Availability Impact |
Impact Bias |
|
Remote |
Low |
Required |
Complete |
Complete |
Complete |
Normal |
|
CVSS Temporal Score - 5.0 |
||||||
|
Exploitability |
Remediation Level |
Report Confidence |
||||
|
Functional |
Official Fix |
Confirmed |
||||
|
CSCse18250 ( registered customers only) - CSRadius Service crashes when processing a specially crafted Access-Request packet. |
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|---|---|---|---|---|---|---|
|
CVSS Base Score - 3.3 |
||||||
|
Access Vector |
Access Complexity |
Authentication |
Confidentiality Impact |
Integrity Impact |
Availability Impact |
Impact Bias |
|
Remote |
Low |
Not Required |
None |
None |
Complete |
Normal |
|
CVSS Temporal Score - 2.7 |
||||||
|
Exploitability |
Remediation Level |
Report Confidence |
||||
|
Functional |
Official Fix |
Confirmed |
||||
|
CSCeg04788 ( registered customers only) - CSRadius Service crashes when processing a specially crafted Access-Request packet. |
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|---|---|---|---|---|---|---|
|
CVSS Base Score - 3.3 |
||||||
|
Access Vector |
Access Complexity |
Authentication |
Confidentiality Impact |
Integrity Impact |
Availability Impact |
Impact Bias |
|
Remote |
Low |
Not Required |
None |
None |
Complete |
Normal |
|
CVSS Temporal Score - 2.7 |
||||||
|
Exploitability |
Remediation Level |
Report Confidence |
||||
|
Functional |
Official Fix |
Confirmed |
||||
|
CSCeg04666 ( registered customers only) - CSRadius Service crashes when processing a specially crafted Access-Request packet. |
||||||
|---|---|---|---|---|---|---|
|
CVSS Base Score - 3.3 |
||||||
|
Access Vector |
Access Complexity |
Authentication |
Confidentiality Impact |
Integrity Impact |
Availability Impact |
Impact Bias |
|
Remote |
Low |
Not Required |
None |
None |
Complete |
Normal |
|
CVSS Temporal Score - 2.7 |
||||||
|
Exploitability |
Remediation Level |
Report Confidence |
||||
|
Functional |
Official Fix |
Confirmed |
||||
Impact
Specially Crafted HTTP GET Request Vulnerability
Successful exploitation may result in the web administrative interface being unavailable until the CSAdmin Service is restarted from windows control panel. Normal Authentication, Authorization and Accounting (AAA) processing will continue. This vulnerability may allow arbitrary code execution if successfully exploited.
Specially Crafted RADIUS Accounting-Request Vulnerability
Successful exploitation may result in RADIUS Authentication, Authorization and Accounting processing to not be performed until the CSRadius service is restarted. TACACS+ Authentication, Authorization and Accounting (AAA) processing will continue. Repeated exploitation could result in a sustained Denial-of-Service (DoS) condition of the RADIUS AAA services. This vulnerability may allow arbitrary code execution if successfully exploited.
Specially Crafted RADIUS Access-Request Vulnerabilities
Successful exploitation may result in RADIUS Authentication, Authorization and Accounting processing to not be performed as the CSRadius service restarts. TACACS+ Authentication, Authorization and Accounting (AAA) processing will continue. Repeated exploitation could result in a sustained Denial-of-Service (DoS) condition of the RADIUS AAA services.
Software Versions and Fixes
When considering software upgrades, also consult http://www.cisco.com/go/psirt and any subsequent advisories to determine exposure and a complete upgrade solution.
In all cases, customers should exercise caution to be certain the devices to be upgraded contain sufficient memory and that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, contact the Cisco Technical Assistance Center (TAC) or your contracted maintenance provider for assistance.
Each row of the software table (below) describes one of the vulnerabilities described in this document. For each vulnerability the earliest possible Release that contains the fix is listed in the "Availability of First Fixed Release" column. A device running a release that is earlier than the release in a specific column (less than the First Fixed Release) is known to be vulnerable. The release should be upgraded at least to the indicated release or a later version (greater than or equal to the First Fixed Release label) or the appropriate patch applied.
|
Vulnerability |
Major Software Release |
Availability of First Fixed Releases * |
|---|---|---|
|
HTTP Vulnerability |
3.1(X) |
Vulnerable; Contact TAC |
|
3.2(X) |
Vulnerable; Contact TAC |
|
|
3.3(X) |
3.3(4) Build 12. |
|
|
4.0(X) |
Apply patch **. |
|
|
4.1(X) |
Are not vulnerable |
|
|
Accounting-Request Vulnerability |
3.1(X) |
Vulnerable; Contact TAC |
|
3.2(X) |
Vulnerable; Contact TAC |
|
|
3.3(X) |
3.3(4) Build 12. |
|
|
4.0(X) |
4.0(1) Build 27. |
|
|
4.1(X) |
Are not vulnerable |
|
|
Access-Request Vulnerabilities |
3.1(X) |
Vulnerable; Contact TAC |
|
3.2(X) |
Vulnerable; Contact TAC |
|
|
3.3(X) |
3.3(3) Build 11. |
|
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4.0(X) |
4.0(1) Build 27. |
|
|
4.1(X) |
Are not vulnerable |
|
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Notes: * 3.3(4) Build 12 is available by contacting Cisco TAC. The patch for the HTTP Vulnerability (CSCsd96293 ( registered customers only) ) is available for download from Cisco Secure ACS for Windows: http://www.cisco.com/pcgi-bin/tablebuild.pl/acs-win-3des?psrtdcat20e2
Cisco Secure ACS Solution Engine: http://www.cisco.com/pcgi-bin/tablebuild.pl/acs-soleng-3des?psrtdcat20e2
Note: Installing the above patch is mutually exclusive with an older patch for CSAdmin, which is also a security related fix - CSCse26719, which is referenced in a previous Cisco Security Response at http://tools.cisco.com/security/center/content/CiscoSecurityResponse/cisco-sr-20060623-acs. A combined patch, which addresses both the above vulnerabilities, has been posted for ACS-4.0.1 (builds 27 and 49), for windows and ACS Solution Engine (build 44) at the following locations: Cisco Secure ACS for Windows: http://www.cisco.com/pcgi-bin/tablebuild.pl/acs-win-3des?psrtdcat20e2
Cisco Secure ACS Solution Engine: http://www.cisco.com/pcgi-bin/tablebuild.pl/acs-soleng-3des?psrtdcat20e2
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Workarounds
For Cisco Secure ACS for Windows and Cisco Secure ACS Solution Engine to help mitigate the risks of these vulnerabilities, the following mitigations have been provided.
The effectiveness of any mitigation 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 mitigation or fix is the most appropriate for use in the intended network before it is deployed.
Additional mitigations that can be deployed on Cisco devices within the network are available in the Cisco Applied Mitigation Bulletin companion document for this advisory: http://tools.cisco.com/security/center/content/CiscoAppliedMitigationBulletin/cisco-amb-20070105-csacs
-
Infrastructure ACLs (iACL)
Apply access control lists (ACLs) on routers, switches and firewalls that filter traffic to the ACS so that traffic is only allowed from stations that need to remotely administer the box, or be authenticated, authorized, or provide accounting data against/to the ACS server. Refer to http://www.cisco.com/en/US/tech/tk648/tk361/technologies_white_paper09186a00801a1a55.shtml for examples on infrastructure ACLs. -
Anti-Spoofing
To prevent spoofed IP packets with the source IP address set to that of the Cisco Secure ACS administrative management station from reaching the Cisco Secure ACS server, utilize anti-spoofing techniques. For more information on utilizing ACLs for anti-spoofing, refer to http://www.cisco.com/en/US/tech/tk648/tk361/technologies_white_paper09186a00801a1a55.shtml and http://www.ietf.org/rfc/rfc2827.txt.
The Unicast Reverse Path Forwarding (Unicast RPF) feature helps to mitigate problems that are caused by forged IP source addresses that are passing through a router. Refer to http://www.cisco.com/en/US/docs/ios/12_2/security/configuration/guide/scfrpf.html for more information.
Obtaining Fixed Software
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 http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.html , or as otherwise set forth at Cisco.com Downloads at http://www.cisco.com/public/sw-center/sw-usingswc.shtml .
Do not contact psirt@cisco.com or security-alert@cisco.com for software upgrades
Customers with Service Contracts
Customers Using Third-Party Support Organizations
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 Without Service Contracts
Customers who purchase direct from Cisco but do not hold a Cisco service contract, and customers who purchase through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should acquire 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)
- e-mail: tac@cisco.com
Customers should have their product serial number available and be prepared to give the URL of this notice as evidence of entitlement to a free upgrade. Free upgrades for non-contract customers must be requested through the TAC.
Refer to http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html for additional TAC contact information, including localized telephone numbers, and instructions and e-mail addresses for use in various languages.
Exploitation and Public Announcements
The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.
Several of these vulnerabilities were reported to Cisco by CESG's Vulnerability Research Group and National Infrastructure Security Co-ordination Centre (NISCC).
Status of This Notice: Final
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.
Distribution
This advisory is posted on Cisco's worldwide website at:
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20070105-csacs
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
- first-teams@first.org
- bugtraq@securityfocus.com
- vulnwatch@vulnwatch.org
- cisco@spot.colorado.edu
- cisco-nsp@puck.nether.net
- full-disclosure@lists.grok.org.uk
- comp.dcom.sys.cisco@newsgate.cisco.com
Future updates of this advisory, if any, will be placed on Cisco's worldwide website, but may or may not be actively announced on mailing lists or newsgroups. Users concerned about this problem are encouraged to check the above URL for any updates.
Revision History
|
Revision 1.0 |
2007-January-18 |
Updates to Software table |
|
Revision 1.0 |
2007-January-12 |
Note updates |
|
Revision 1.0 |
2007-January-05 |
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 website at http://www.cisco.com/en/US/products/products_security_vulnerability_policy.html. This includes instructions for press inquiries regarding Cisco security notices. All Cisco security advisories are available at http://www.cisco.com/go/psirt.
