CVE-2021-1591 Explained : Impact and Mitigation
Learn about CVE-2021-1591, a critical vulnerability in Cisco Nexus 9500 Series Switches allowing remote attackers to bypass ACL rules and access network resources. Find mitigation steps here.
A vulnerability in the EtherChannel port subscription logic of Cisco Nexus 9500 Series Switches could allow an unauthenticated, remote attacker to bypass access control list (ACL) rules that are configured on an affected device.
Understanding CVE-2021-1591
This CVE identifies a critical vulnerability in Cisco Nexus 9500 Series Switches affecting the EtherChannel port subscription logic.
What is CVE-2021-1591?
The vulnerability allows remote attackers to circumvent ACL rules on the device, potentially gaining unauthorized access to network resources protected by the ACL.
The Impact of CVE-2021-1591
If successfully exploited, this vulnerability could compromise the security of network resources that are supposed to be safeguarded by the ACL on the port channel interface.
Technical Details of CVE-2021-1591
The vulnerability stems from oversubscription of resources when ACLs are applied to port channel interfaces on Cisco Nexus 9500 Series Switches.
Vulnerability Description
The issue lies in the EtherChannel port subscription logic, enabling attackers to bypass configured ACL rules and gain unauthorized access to protected network resources.
Affected Systems and Versions
The vulnerability affects Cisco NX-OS Software with the affected versions yet to be specified.
Exploitation Mechanism
By exploiting the oversubscription of resources in applying ACLs to port channel interfaces, attackers can attempt access to network resources protected by the ACL.
Mitigation and Prevention
To safeguard against potential exploits stemming from CVE-2021-1591, immediate action and long-term security practices must be implemented.
Immediate Steps to Take
Ensure network security by monitoring and restricting unauthorized access, especially for devices vulnerable to the bypass vulnerability.
Long-Term Security Practices
Regularly update and patch affected systems to enhance security measures and prevent exploitation of vulnerabilities.
Patching and Updates
Stay informed about security advisories from Cisco and apply relevant patches and updates to mitigate the risk of unauthorized access.