A vulnerability in how Cisco Firepower Threat Defense (FTD) Software handles session timeouts for management connections could allow an unauthenticated, remote attacker to cause a buildup of remote management connections to an affected device, which could result in a denial of service (DoS) condition.
The vulnerability exists because the default session timeout period for specific to-the-box remote management connections is too long. An attacker could exploit this vulnerability by sending a large and sustained number of crafted remote management connections to an affected device, resulting in a buildup of those connections over time. A successful exploit could allow the attacker to cause the remote management interface or Cisco Firepower Device Manager (FDM) to stop responding and cause other management functions to go offline, resulting in a DoS condition. The user traffic that is flowing through the device would not be affected, and the DoS condition would be isolated to remote management only.
There are no workarounds that address this vulnerability.
This advisory is available at the following link:
At the time of publication, this vulnerability affected Cisco FTD Software releases earlier than Release 184.108.40.206 and Release 220.127.116.11.
For information about which Cisco software releases are vulnerable, 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.
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.
If this vulnerability is being exploited, administrators may see the following system error logging message on the console or in the logging file:
HTTP: [mpm_worker:error] server reached MaxRequestWorkers setting, consider raising the MaxRequestWorkers setting
Administrators are advised to contact the Cisco Technical Assistance Center (TAC) to review the device logs to determine if this vulnerability is being exploited.
There are no workarounds that address this vulnerability.
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.
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 described in this advisory and which release included the fix for this vulnerability.
Cisco FTD Software
Cisco FTD Software Release First Fixed Release for This Vulnerability Earlier than 6.1.01 Migrate to a fixed release. 6.1.0 Migrate to a fixed release. 6.2.0 Migrate to a fixed release. 6.2.1 Migrate to a fixed release. 6.2.2 Migrate to a fixed release. 6.2.3 Migrate to a fixed release. 6.3.0 Migrate to a fixed release. 6.4.0 18.104.22.168 6.5.0 22.214.171.124 (future release)
Cisco_FTD_Hotfix_H-126.96.36.199-2.sh.REL.tar and later
Cisco_FTD_SSP_FP1K_Hotfix_H-188.8.131.52-2.sh.REL.tar and later
Cisco_FTD_SSP_FP2K_Hotfix_H-184.108.40.206-2.sh.REL.tar and later
Cisco_FTD_SSP_Hotfix_H-220.127.116.11-2.sh.REL.tar and later
6.6.0 Not vulnerable.
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.
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.
This vulnerability was found by Santosh Krishnamurthy of Cisco during internal security testing.
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.
Version Description Section Status Date 1.1 Updated Hot Fixes for FTD releases 6.4.0 and 6.5.0. Fixed Releases Final 2020-MAY-15 1.2 Updated fixed release information for FTD Release 6.4.0. Fixed Releases Final 2020-MAY-06 1.0 Initial public release. — Final 2020-MAY-06
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