CVE-2018-17205 : What You Need to Know

A vulnerability has been discovered in versions 2.7.x through 2.7.6 of Open vSwitch (OvS) that can lead to an OvS crash due to an assertion failure in the ofproto_rule_insert__ function.

Understanding CVE-2018-17205

This CVE involves a specific vulnerability in Open vSwitch (OvS) versions 2.7.x through 2.7.6 that can result in a system crash.

What is CVE-2018-17205?

This vulnerability occurs in the ofproto_rule_insert__ function within ofproto/ofproto.c in OvS. It arises during a bundle commit when flows added within the bundle are applied to ofproto in a particular order. If a flow cannot be added, OvS attempts to revert all previously applied flows from the same bundle, leading to an assertion failure and subsequent crash.

The Impact of CVE-2018-17205

The assertion failure caused by this vulnerability can result in an Open vSwitch (OvS) crash, potentially disrupting network operations and causing system instability.

Technical Details of CVE-2018-17205

This section provides more in-depth technical details about the vulnerability.

Vulnerability Description

The issue lies in the ofproto_rule_insert__ function within ofproto/ofproto.c in Open vSwitch (OvS) versions 2.7.x through 2.7.6. During a bundle commit, if a flow cannot be added, OvS attempts to revert previously applied flows, triggering an assertion failure due to a rule state mismatch.

Affected Systems and Versions

Product: Open vSwitch (OvS)
Versions: 2.7.x through 2.7.6

Exploitation Mechanism

Flows added within a bundle are applied to ofproto in a specific order.
If a flow cannot be added, OvS tries to revert all previously applied flows from the same bundle.
Assertion failure occurs due to a rule state mismatch, leading to an OvS crash.

Mitigation and Prevention

It is crucial to take immediate steps to address and prevent the exploitation of this vulnerability.

Immediate Steps to Take

Apply patches provided by the vendor to fix the vulnerability.
Monitor vendor advisories for updates and security alerts.
Implement network segmentation to limit the impact of potential attacks.

Long-Term Security Practices

Regularly update and patch software to protect against known vulnerabilities.
Conduct security assessments and audits to identify and mitigate risks.
Educate network administrators and users about best security practices.

Patching and Updates

Ensure that all affected systems are updated with the latest patches from the vendor.
Regularly check for security advisories and updates from Open vSwitch (OvS) to stay informed about potential security issues.