CVE-2022-20943: Medium severity Cisco Firepower Threat Defense vulnerability
Multiple vulnerabilities in the Server Message Block Version 2 (SMB2) processor of the Snort detection engine on multiple Cisco products could allow an unauthenticated, remote attacker to bypass the configured policies or cause a denial of service (DoS) condition on an affected device. These vulnerabilities are due to improper management of system resources when the Snort detection engine is processing SMB2 traffic. An attacker could exploit these vulnerabilities by sending a high rate of certain types of SMB2 packets through an affected device. A successful exploit could allow the attacker to trigger a reload of the Snort process, resulting in a DoS condition. Note: When the snort preserve-connection option is enabled for the Snort detection engine, a successful exploit could also allow the attacker to bypass the configured policies and deliver a malicious payload to the protected network. The snort preserve-connection setting is enabled by default. See the Details ["#details"] section of this advisory for more information. Note: Only products that have Snort 3 configured are affected. Products that are configured with Snort 2 are not affected.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Disable the Snort preserve-connection option (it is enabled by default) to prevent a successful exploit from bypassing configured policies and delivering a malicious payload to the protected network.
Snort detection engine snort preserve-connection = disabled - Compensating control
For products with Snort 3 configured, restrict SMB2 traffic by using network controls (e.g., firewall/ACL) to block or limit high-rate SMB2 packet types reaching the Snort detection engine, reducing the ability to trigger the resource-management flaw that can bypass policies or cause DoS.
Event History
Frequently Asked Questions
What is CVE-2022-20943?
CVE-2022-20943 is a vulnerability in the SMB2 processor of the Snort detection engine on multiple Cisco products.
Which Cisco products are affected by CVE-2022-20943?
Multiple Cisco products, including Cisco Firepower Threat Defense and Cisco Meraki MX Security Appliance Firmware, are affected by CVE-2022-20943.
What is the severity of CVE-2022-20943?
The severity of CVE-2022-20943 is medium, with a CVSS score of 5.8.
What can an unauthenticated, remote attacker do with CVE-2022-20943?
An unauthenticated, remote attacker could bypass configured policies or cause a denial of service (DoS) condition on affected devices.
Where can I find more information about CVE-2022-20943?
You can find more information about CVE-2022-20943 in the Cisco Security Advisory.