CVE-2019-15847 : Vulnerability Insights and Analysis

This CVE involves a vulnerability in the GNU Compiler Collection (GCC) affecting the randomness of the random number generator due to optimization issues in the POWER9 backend.

Understanding CVE-2019-15847

This CVE highlights a specific issue in the GCC related to the __builtin_darn intrinsic calls and their impact on the randomness of generated numbers.

What is CVE-2019-15847?

The vulnerability in the GCC's POWER9 backend before version 10 allowed for the consolidation of multiple __builtin_darn intrinsic calls into a single call, leading to reduced randomness in the random number generator due to the lack of a specified volatile operation. This resulted in identical outputs for all __builtin_darn() calls within a program execution.

The Impact of CVE-2019-15847

The vulnerability could potentially weaken the security of systems relying on random number generation for cryptographic operations or other sensitive functions, as the predictability of generated numbers could be exploited by malicious actors.

Technical Details of CVE-2019-15847

This section delves into the specific technical aspects of the CVE.

Vulnerability Description

The issue stemmed from the GCC's optimization of __builtin_darn intrinsic calls, which omitted specifying a volatile operation, leading to decreased entropy in the random number generator.

Affected Systems and Versions

Systems using GCC with a POWER9 backend before version 10
Versions of GCC prior to version 10

Exploitation Mechanism

Exploiting the lack of randomness in generated numbers to potentially predict outcomes of cryptographic operations or other security-sensitive processes

Mitigation and Prevention

To address and prevent the CVE-2019-15847 vulnerability, consider the following steps:

Immediate Steps to Take

Update GCC to version 10 or newer to mitigate the issue
Implement additional entropy sources or cryptographic mechanisms to enhance randomness

Long-Term Security Practices

Regularly update compilers and development tools to the latest versions
Conduct thorough testing of random number generation functions in critical applications

Patching and Updates

Stay informed about security advisories and patches from GCC and related distributions