CVE-2018-0239 : Exploit Details and Defense Strategies

A security flaw has been discovered in the Cisco StarOS operating system, affecting Cisco Aggregation Services Router (ASR) 5700 Series devices and Virtualized Packet Core (VPC) System Software.

Understanding CVE-2018-0239

This CVE involves a vulnerability in the egress packet processing functionality of Cisco StarOS, potentially leading to a denial of service condition.

What is CVE-2018-0239?

The vulnerability allows an unauthenticated remote attacker to disrupt packet forwarding through a device's interface by sending specially crafted IP packets or fragments.

The Impact of CVE-2018-0239

Attackers can cause the network interface to cease forwarding packets, leading to a denial of service condition.
Affected devices may need manual reloading to clear the issue.

Technical Details of CVE-2018-0239

This section provides more in-depth technical insights into the vulnerability.

Vulnerability Description

Failure to properly verify the length of transmitted packets against the maximum allowed length set for the network interface card (NIC) leads to the vulnerability.
Exploitation involves sending crafted IP packets or fragments through a device's interface.

Affected Systems and Versions

Cisco products running the StarOS operating system with a virtual interface card installed are impacted.
Specifically affects Aggregation Services Router (ASR) 5700 Series and Virtualized Packet Core System Software.

Exploitation Mechanism

Attackers exploit the vulnerability by sending crafted IP packets or fragments through a device's interface.
Both IPv4 and IPv6 network traffic can trigger the vulnerability.

Mitigation and Prevention

Steps to address and prevent the CVE-2018-0239 vulnerability.

Immediate Steps to Take

Apply relevant patches and updates provided by Cisco.
Monitor network traffic for any signs of exploitation.
Implement network segmentation to limit the impact of potential attacks.

Long-Term Security Practices

Regularly update and patch all network devices and software.
Conduct security audits and assessments to identify vulnerabilities proactively.

Patching and Updates

Cisco has released patches to address the vulnerability, and affected devices should be updated promptly to mitigate the risk.