CVE-2019-17023 : Security Advisory and Response
Learn about CVE-2019-17023 affecting Firefox versions before 72, allowing improper state transitions in TLS negotiation. Find mitigation steps and system protection measures.
A security vulnerability in Firefox versions prior to 72 allows for an improper state transition in the TLS State Machine when negotiating a protocol lower than TLS 1.3 after a HelloRetryRequest. This flaw can lead to the disregarding of incoming Application Data records.
Understanding CVE-2019-17023
This CVE entry highlights a vulnerability in Firefox versions before 72 that affects the TLS protocol negotiation process.
What is CVE-2019-17023?
The vulnerability arises when a client, following a HelloRetryRequest, opts to negotiate a protocol lower than TLS 1.3, causing an incorrect state transition in the TLS State Machine. Consequently, any incoming Application Data records are ignored due to this security flaw.
The Impact of CVE-2019-17023
The vulnerability impacts Firefox versions earlier than 72, potentially leading to the disregarding of incoming Application Data records, affecting the integrity of data transmission.
Technical Details of CVE-2019-17023
This section delves into the technical aspects of the CVE, including the vulnerability description, affected systems, and exploitation mechanism.
Vulnerability Description
The flaw allows clients to negotiate a protocol lower than TLS 1.3 after a HelloRetryRequest, resulting in an improper state transition in the TLS State Machine, leading to the ignoring of incoming Application Data records.
Affected Systems and Versions
- Product: Firefox
- Vendor: Mozilla
- Versions Affected: Before 72
Exploitation Mechanism
The vulnerability is exploited by initiating a HelloRetryRequest and subsequently negotiating a protocol lower than TLS 1.3, triggering the improper state transition in the TLS State Machine.
Mitigation and Prevention
To address CVE-2019-17023, immediate steps and long-term security practices are essential.
Immediate Steps to Take
- Update Firefox to version 72 or above to mitigate the vulnerability.
- Monitor vendor advisories for security patches and updates.
Long-Term Security Practices
- Regularly update browsers and software to the latest versions.
- Implement network security measures to detect and prevent potential exploits.
- Educate users on safe browsing practices to minimize security risks.
Patching and Updates
- Apply security patches provided by Mozilla promptly to address the vulnerability and enhance system security.