A vulnerability in the antispam protection mechanisms of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass the URL reputation filters on an affected device.
This vulnerability is due to improper processing of URLs. An attacker could exploit this vulnerability by crafting a URL in a particular way. A successful exploit could allow the attacker to bypass the URL reputation filters that are configured for an affected device, which could allow malicious URLs to pass through the device.
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:
At the time of publication, this vulnerability affected Cisco AsyncOS Software for Cisco ESA releases earlier than Release 14.0.1.
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.
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 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 AsyncOS Software for Cisco Email Security Appliance First Fixed Release Earlier than 14.0 Migrate to a fixed release. 14.0 14.0.1
The fixed release is not available from the Software Center at Cisco.com. Administrators can upgrade the software through the GUI or CLI.
In most cases, the software can be upgraded over the network by using the System Upgrade options in the web interface of Cisco ESA. To upgrade a device using the web interface, do the following:
- Choose System Administration > System Upgrade.
- Click Upgrade Options.
- Choose Download and Install.
- Choose the appropriate release.
- In the Upgrade Preparation area, choose the appropriate options.
- Click Proceed to begin the upgrade. A progress bar will display the status of the upgrade. After the upgrade is complete, the device will reboot.
The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.
The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
This vulnerability was found 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 1.0 Initial public release. — Final 2021-OCT-06
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