Summary

• A vulnerability in the External RESTful Services (ERS) API of Cisco Identity Services Engine (ISE) Software could allow an authenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the interface of an affected device.

  This vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by persuading an authenticated administrator of the web-based management interface to click a malicious link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information.

  Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

  This advisory is available at the following link:
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ise-xss-twLnpy3M

Affected Products

• Vulnerable Products

  At the time of publication, this vulnerability affected Cisco ISE Software if ERS was enabled.

  For information about which Cisco software releases were vulnerable at the time of publication, see the Fixed Software section of this advisory. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.

  Determine Whether ERS is Enabled

  For Cisco ISE releases 2.0 to 2.7, do the following:

  1. Log in to the Cisco ISE web management interface.
  2. Choose Administration > System > Settings.
  3. Choose ERS Settings.
     • If Enable ERS for Read/Write is selected, the device is vulnerable.
     • If Disable ERS is selected, the device is not vulnerable.

  For Cisco ISE Release 3.0, do the following:

  1. Log in to the Cisco ISE web management interface.
  2. Click the menu icon.
  3. Choose Administration > System > Settings.
  4. Choose ERS Settings.
     • If Enable ERS for Read/Write is selected, the device is vulnerable.
     • If Disable ERS is selected, the device is not vulnerable.

  For Cisco ISE releases 3.1 and 3.2, do the following:

  1. Log in to the Cisco ISE web management interface.
  2. Click the menu icon.
  3. Choose Administration > System > Settings.
  4. Choose API Settings.
  5. Choose the API Service Settings tab.
  • If ERS (Read/Write) is selected, the device is vulnerable.
  • If ERS (Read/Write) is not selected, the device is not vulnerable.

   

  Products Confirmed Not Vulnerable

  Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.

Workarounds

• There are no workarounds that address this vulnerability. However, administrators may disable the affected feature.

  To disable ERS in Cisco ISE releases 2.0 to 2.7, do the following:

  1. Log in to the Cisco ISE web management interface.
  2. Choose Administration > System > Settings.
  3. Choose ERS Settings.
  4. Click the Disable ERS radio button.

  To disable ERS in Cisco ISE Release 3.0, do the following:

  1. Log in to the Cisco ISE web management interface.
  2. Click the menu icon.
  3. Choose Administration > System > Settings.
  4. Click the Disable ERS radio button.

  To disable ERS in Cisco ISE releases 3.1 and 3.2, do the following:

  1. Log in to the Cisco ISE web management interface.
  2. Click the menu icon.
  3. Choose Administration > System > Settings.
  4. Choose API Settings.
  5. Choose the API Service Settings tab.
  6. Click the ERS (Read/Write) toggle switch to deactivate it.

  While this mitigation has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

Fixed Software

• When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories page, to determine exposure and a complete upgrade solution.

  In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.

  Fixed Releases

  At the time of publication, the release information in the following table(s) was accurate. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.

  The left column lists Cisco software releases, and the right column indicates whether a release was affected by the vulnerability that is described in this advisory and which release included the fix for this vulnerability.

  Cisco ISE Software Release	First Fixed Release
  2.41 and earlier	Migrate to fixed release.
  2.62	Migrate to fixed release.
  2.7	2.7P8
  3.0	3.0P7
  3.1	3.1P4
  3.2	3.2P1

  1. Cisco ISE Software Release 2.4 has reached End of Software Maintenance. Customers are advised to migrate to a supported release that includes the fix for this vulnerability.

  2. Hot patches for 2.6P12 are available by request. Contact Cisco TAC to make the request.

  For instructions on upgrading your device, see the Upgrade Guides located on the Cisco Identity Service Engine support page.

  The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.

Exploitation and Public Announcements

• The Cisco PSIRT is aware that proof-of-concept exploit code is available for the vulnerability that is described in this advisory.

  The Cisco PSIRT is not aware of any malicious use of the vulnerability that is described in this advisory.

Source

• Cisco would like to thank Davide Virruso of Yoroi for reporting this vulnerability.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ise-xss-twLnpy3M

Revision History

• Version	Description	Section	Status	Date
  1.3	Updated fixed release and hot patch information. Added that proof-of-concept code is now available.	Fixed Releases and Exploitation and Public Announcements	Final	2023-MAR-31
  1.2	Updated hot patch information.	Fixed Releases	Final	2022-NOV-14
  1.1	Added mitigation information. Updated expected release date for 2.7P8.	Workarounds and Fixed Releases	Final	2022-OCT-31
  1.0	Initial public release.	—	Final	2022-OCT-19

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