CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N/E:X/RL:X/RC:X
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A vulnerability in the Transport Layer Security version 1.3 (TLS 1.3) policy with URL category functionality for Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass a configured TLS 1.3 policy to block traffic for a specific URL.
The vulnerability is due to a logic error with Snort handling of the connection with the TLS 1.3 policy and URL category configuration. An attacker could exploit this vulnerability by sending crafted TLS 1.3 connections to an affected device. A successful exploit could allow the attacker to bypass the TLS 1.3 policy and access URLs that are outside the affected device and normally would be dropped.
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-ssl-bypass-O5tGum2n
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Vulnerable Products
At the time of publication, this vulnerability affected Cisco FTD Software releases 6.4.0 through 6.4.0.8 with an SSL/TLS policy with URL category configured.
See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
Cisco has confirmed that this vulnerability does not affect Cisco Adaptive Security Appliance (ASA) Software or Cisco Firepower Management Center (FMC) Software.
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There are no workarounds that address this vulnerability.
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When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts 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 Release
At the time of publication, Cisco expected to fix this vulnerability in Cisco FTD Software Release 6.4.0.9, scheduled for May 2020.1 Cisco FTD Software releases earlier than Release 6.4.0 are not vulnerable.
See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.
1. Cisco FMC and FTD Software releases 6.0.1 and earlier have reached end of software maintenance. Customers are advised to migrate to a supported release that includes the fix for this vulnerability.
To upgrade to a fixed release of Cisco FTD Software, customers can do one of the following:
- For devices that are managed by using Cisco Firepower Management Center (FMC), use the FMC interface to install the upgrade. After installation is complete, reapply the access control policy.
- For devices that are managed by using Cisco Firepower Device Manager (FDM), use the FDM interface to install the upgrade. After installation is complete, reapply the access control policy.
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The Cisco Product Security Incident Response Team (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 internal security testing.
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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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Version Description Section Status Date 1.0 Initial public release. — Final 2020-MAY-06
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