CVE-2019-15651 Explained : Impact and Mitigation

wolfSSL 4.1.0 library contains a vulnerability in the DecodeCertExtensions function that leads to a one-byte heap-based buffer over-read. This issue arises when processing a specially crafted DER certificate.

Understanding CVE-2019-15651

In the file wolfcrypt/src/asn.c of the wolfSSL 4.1.0 library, a vulnerability allows a one-byte heap-based buffer over-read in the DecodeCertExtensions function.

What is CVE-2019-15651?

The vulnerability occurs due to mishandling the reading of the ASN_BOOLEAN byte in the GetLength_ex function while processing a specially crafted DER certificate.

The Impact of CVE-2019-15651

This vulnerability could be exploited by an attacker to cause a denial of service or potentially disclose sensitive information from the affected system.

Technical Details of CVE-2019-15651

The technical details of the vulnerability in wolfSSL 4.1.0 library are as follows:

Vulnerability Description

Vulnerability Type: Heap-based Buffer Over-read
Location: DecodeCertExtensions function in wolfcrypt/src/asn.c

Affected Systems and Versions

Affected Version: wolfSSL 4.1.0
Affected Component: DecodeCertExtensions function

Exploitation Mechanism

The vulnerability is exploited by crafting a malicious DER certificate to trigger the mishandling of the ASN_BOOLEAN byte in the GetLength_ex function.

Mitigation and Prevention

To address CVE-2019-15651, follow these mitigation steps:

Immediate Steps to Take

Update wolfSSL to a non-vulnerable version.
Monitor vendor security advisories for patches.

Long-Term Security Practices

Regularly update software and libraries to the latest versions.
Implement secure coding practices to prevent buffer over-read vulnerabilities.

Patching and Updates

Apply patches provided by wolfSSL promptly to fix the vulnerability and enhance system security.