CVE-2019-15703 : Security Advisory and Response

This CVE-2019-15703 article provides insights into a vulnerability in Fortinet FortiOS versions 6.2.1, 6.2.0, and 6.0.8, leading to information disclosure due to insufficient entropy in the pseudo-random number generator (PRNG).

Understanding CVE-2019-15703

This CVE involves a lack of sufficient entropy in the PRNG of Fortinet FortiOS versions, potentially enabling attackers to retrieve sensitive information.

What is CVE-2019-15703?

The vulnerability in Fortinet FortiOS versions 6.2.1, 6.2.0, and 6.0.8, and earlier, allows attackers to exploit the PRNG's lack of entropy to potentially recover long-term ECDSA secrets in TLS clients.

The Impact of CVE-2019-15703

The vulnerability can lead to information disclosure, specifically affecting devices without enabled hardware TRNG tokens and models lacking built-in TRNG seeds. Attackers can leverage this to retrieve sensitive information through specific attack methods.

Technical Details of CVE-2019-15703

This section delves into the technical aspects of the CVE, including the vulnerability description, affected systems, and exploitation mechanisms.

Vulnerability Description

The vulnerability arises from insufficient entropy in the PRNG of Fortinet FortiOS versions, enabling attackers to potentially recover long-term ECDSA secrets in TLS clients.

Affected Systems and Versions

Product: Fortinet FortiOS
Vendor: Fortinet
Affected Versions: 6.2.1, 6.2.0, 6.0.8, and below

Exploitation Mechanism

Attackers can exploit the lack of entropy in the PRNG to retrieve sensitive information in TLS clients using specific attack methods.

Mitigation and Prevention

To address CVE-2019-15703, immediate steps and long-term security practices are crucial.

Immediate Steps to Take

Update affected Fortinet FortiOS versions to patched releases promptly.
Implement additional security measures to mitigate information disclosure risks.

Long-Term Security Practices

Regularly monitor for security updates and patches from Fortinet.
Enhance network security measures to prevent potential attacks exploiting PRNG vulnerabilities.

Patching and Updates

Apply patches provided by Fortinet to address the PRNG entropy issue and enhance system security.