Cisco Security Advisory
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CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:X/RL:X/RC:X
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A vulnerability in the external authentication mechanism of Cisco Modeling Labs could allow an unauthenticated, remote attacker to access the web interface with administrative privileges.
This vulnerability is due to the improper handling of certain messages that are returned by the associated external authentication server. An attacker could exploit this vulnerability by logging in to the web interface of an affected server. Under certain conditions, the authentication mechanism would be bypassed and the attacker would be logged in as an administrator. A successful exploit could allow the attacker to obtain administrative privileges on the web interface of an affected server, including the ability to access and modify every simulation and all user-created data. To exploit this vulnerability, the attacker would need valid user credentials that are stored on the associated external authentication server.
Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cml-auth-bypass-4fUCCeG5
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Vulnerable Products
This vulnerability affects the following Cisco products if they are configured with LDAP authentication:
- Modeling Labs for Education
- Modeling Labs Enterprise
- Modeling Labs - Not For Resale
For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory.
Determine Whether LDAP Authentication is Configured
To determine whether LDAP authentication is configured, log in to Cisco Modeling Labs and choose Tools > System Administration > User Authentication.
For more information, see Configuring LDAP Authentication.
Products Confirmed Not Vulnerable
Cisco has confirmed that this vulnerability does not affect the following Cisco products:
- Modeling Labs - Personal
- Modeling Labs - Personal Plus
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
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This vulnerability can be exploited only under specific conditions that are determined by how the associated LDAP authentication server responds to authentication queries that come from Cisco Modeling Labs.
If the LDAP server is configured in such a way that it will reply to search queries with a non-empty array of matching entries (replies that contain search result reference entries), this authentication bypass vulnerability can be exploited.
This is not a configuration setting that can be influenced by an attacker, and only the LDAP server administrator should be able to verify and eventually change this behavior.
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There is a workaround that addresses this vulnerability. As explained in the Details section of this advisory, administrators should verify the LDAP authentication server configuration and ensure that failing search queries do not return non-empty matching result arrays. Methods vary depending on the LDAP server that is deployed. For further guidance, refer to the documentation for the specific LDAP installation.
While this workaround 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.
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Cisco has released free software updates that address the vulnerability described in this advisory. Customers with service contracts that entitle them to regular software updates should obtain security fixes through their usual update channels.
Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:
https://www.cisco.com/c/en/us/products/end-user-license-agreement.htmlAdditionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.
The Cisco Support and Downloads page on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool.
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.
Customers Without Service Contracts
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html
Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
Fixed Releases
In the following table, the left column lists Cisco software releases. The right column indicates whether a release is affected by the vulnerability that is described in this advisory and the first release that includes the fix for this vulnerability. Customers are advised to upgrade to an appropriate fixed software release as indicated in this section.
Cisco Modeling Labs Release First Fixed Release 2.2 and earlier Not vulnerable. 2.3 Migrate to a fixed release. 2.4 Migrate to a fixed release. 2.5 2.5.1 The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.
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The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
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This vulnerability was found during the resolution of a Cisco TAC support case.
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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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Show LessVersion Description Section Status Date 1.0 Initial public release. — Final 2023-APR-19
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