CVE-2017-3849 : Exploit Details and Defense Strategies

A weakness has been identified in the registrar feature of Cisco IOS Software and Cisco IOS XE Software, potentially affecting versions 15.2 through 15.6 of Cisco IOS Software and versions 3.7 through 3.18 and 16 of Cisco IOS XE Software. This vulnerability could allow an attacker in close proximity and without authentication to disrupt the functioning of a system by causing a denial of service (DoS) situation.

Understanding CVE-2017-3849

This CVE involves a vulnerability in the Autonomic Networking Infrastructure (ANI) registrar feature of Cisco IOS Software and Cisco IOS XE Software.

What is CVE-2017-3849?

The vulnerability allows an unauthenticated attacker in close proximity to trigger a denial of service (DoS) condition by exploiting incomplete input validation on crafted packets.

The Impact of CVE-2017-3849

An attacker can disrupt system functioning by causing a DoS situation without authentication.
Successful exploitation could lead to a reload of the affected device.

Technical Details of CVE-2017-3849

This section provides detailed technical information about the vulnerability.

Vulnerability Description

The vulnerability is caused by incomplete validation of certain constructed packets during input, allowing an attacker to disrupt system functioning.

Affected Systems and Versions

Cisco IOS Software versions 15.2 through 15.6
Cisco IOS XE Software versions 3.7 through 3.18 and 16

Exploitation Mechanism

Attacker sends a specially created autonomic network channel discovery packet to a device with specific characteristics.
The device must run Cisco IOS Software or Cisco IOS XE Software supporting the ANI feature, be configured as an autonomic registrar, and have a whitelist configuration.

Mitigation and Prevention

Protecting systems from CVE-2017-3849 requires immediate steps and long-term security practices.

Immediate Steps to Take

Ensure systems are updated with the latest patches from Cisco.
Implement network segmentation to limit the impact of potential attacks.
Monitor network traffic for any suspicious activity.

Long-Term Security Practices

Regularly update and patch all software and firmware on network devices.
Train employees on security best practices to prevent social engineering attacks.
Conduct regular security audits and penetration testing to identify vulnerabilities.

Patching and Updates

Apply the patches provided by Cisco to address the vulnerability.