CVE-2021-40116 Explained : Impact and Mitigation
Learn about CVE-2021-40116, a critical vulnerability in multiple Cisco products due to Snort rules implementation. Understand its impact, affected systems, and mitigation steps.
Multiple Cisco products are affected by a vulnerability in Snort rules that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This article provides an overview of the CVE-2021-40116 vulnerability.
Understanding CVE-2021-40116
CVE-2021-40116 is a vulnerability in Snort rules impacting multiple Cisco products, potentially leading to a denial of service (DoS) situation on affected devices.
What is CVE-2021-40116?
The vulnerability arises due to improper handling of Block with Reset or Interactive Block with Reset actions in Snort rules. Attackers can exploit this by sending a crafted IP packet to the device, causing through traffic to be dropped.
The Impact of CVE-2021-40116
The vulnerability has a CVSS V3.1 base score of 8.6, with a high availability impact, making it crucial to address promptly. As of the advisory, no public exploitation has been reported.
Technical Details of CVE-2021-40116
This section delves into the specifics of the vulnerability.
Vulnerability Description
The vulnerability allows an unauthenticated, remote attacker to launch a DoS attack by sending a manipulated IP packet to the affected device.
Affected Systems and Versions
- Affected Product: Cisco Firepower Threat Defense Software
- Vendor: Cisco
- Version: n/a
- Other Details: Only products with Snort3 and specific rule configurations are vulnerable.
Exploitation Mechanism
The vulnerability can be exploited by crafting IP packets with specific attributes that trigger the improper handling of rules, resulting in a DoS condition.
Mitigation and Prevention
To safeguard against CVE-2021-40116, follow these mitigation strategies:
Immediate Steps to Take
- Apply vendor-provided patches or updates promptly.
- Implement firewall rules to restrict access to vulnerable services.
- Monitor network traffic for any suspicious activities.
Long-Term Security Practices
- Regularly update and patch all software and firmware.
- Conduct routine security assessments and audits to identify vulnerabilities.
- Educate users and IT staff on best security practices.
Patching and Updates
- Stay informed about security advisories and updates from Cisco.
- Ensure timely installation of security patches to eliminate the vulnerability.