CVE-2019-1691 Explained : Impact and Mitigation

Cisco Firepower Threat Defense Software SSL or TLS Denial of Service Vulnerability

Understanding CVE-2019-1691

This CVE involves a vulnerability in Cisco Firepower Threat Defense Software that could allow an unauthenticated attacker to trigger an unexpected restart of the SNORT detection engine, leading to a denial of service (DoS) scenario.

What is CVE-2019-1691?

The vulnerability arises from inadequate handling of SSL or TLS packet headers during connection establishment, enabling an attacker to send a carefully crafted packet to cause the SNORT detection engine to restart unexpectedly.

The Impact of CVE-2019-1691

The exploit could result in a partial DoS situation until the SNORT detection engine fully restarts. This vulnerability affects versions prior to 6.2.3.4 of the software.

Technical Details of CVE-2019-1691

Vulnerability Description

The flaw in the detection engine of Cisco Firepower Threat Defense Software allows for an unexpected restart of the SNORT detection engine, potentially leading to a DoS scenario.

Affected Systems and Versions

Product: Cisco Firepower Threat Defense Software
Vendor: Cisco
Versions Affected: < 6.2.3.4

Exploitation Mechanism

Attack Complexity: Low
Attack Vector: Network
Availability Impact: Low
Privileges Required: None
Scope: Changed
Vector String: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

Mitigation and Prevention

Immediate Steps to Take

Apply the latest security patches provided by Cisco.
Monitor Cisco's security advisories for updates on this vulnerability.

Long-Term Security Practices

Regularly update and patch all software and systems.
Implement network segmentation and access controls to limit exposure to potential attacks.

Patching and Updates

Cisco has released patches to address this vulnerability. Ensure all affected systems are updated to version 6.2.3.4 or higher.