CVE-2017-3879 : Exploit Details and Defense Strategies

A vulnerability has been identified in the remote login feature of Cisco NX-OS Software on Cisco Nexus 9000 Series Switches, potentially allowing unauthorized remote attackers to terminate the login process abruptly.

Understanding CVE-2017-3879

This CVE involves a Denial of Service vulnerability in the remote login functionality of Cisco NX-OS Software on Cisco Nexus 9000 Series Switches.

What is CVE-2017-3879?

The vulnerability could allow unauthenticated remote attackers to disrupt the login process, leading to failed login attempts. However, it does not impact normal user traffic on the device. Attackers can exploit this issue using Telnet or SSH clients.

The Impact of CVE-2017-3879

Unauthorized remote attackers can terminate the login process, causing login failures.
No impact on regular user traffic through the device.

Technical Details of CVE-2017-3879

This section provides detailed technical information about the vulnerability.

Vulnerability Description

The vulnerability in Cisco NX-OS Software on Cisco Nexus 9000 Series Switches allows attackers to disrupt the login process, resulting in failed login attempts.

Affected Systems and Versions

Affected Product: Cisco Nexus 9000 Series Switches
Vulnerable Versions: 7.0(3)I3(1), 8.3(0)CV(0.342), 8.3(0)CV(0.345)

Exploitation Mechanism

Attackers can exploit the vulnerability using Telnet or SSH clients.

Mitigation and Prevention

Protect your systems from CVE-2017-3879 with the following steps:

Immediate Steps to Take

Disable remote Telnet connections if not required.
Implement firewall rules to restrict access to vulnerable systems.
Monitor network traffic for any suspicious login attempts.

Long-Term Security Practices

Regularly update and patch Cisco NX-OS Software on affected devices.
Conduct security training for users to recognize and report suspicious activities.

Patching and Updates

Ensure that affected systems are updated to the fixed software releases: 8.3(0)CV(0.362), 8.0(1), 7.0(3)IED5(0.19), and other listed versions.