CVE-2019-1563 : Security Advisory and Response

CVE-2019-1563, also known as 'Padding Oracle in PKCS7_dataDecode and CMS_decrypt_set1_pkey,' is a vulnerability in OpenSSL that could allow attackers to exploit decryption attempts and retrieve sensitive information.

Understanding CVE-2019-1563

This CVE entry addresses a specific vulnerability in OpenSSL that could lead to a Bleichenbacher padding oracle attack.

What is CVE-2019-1563?

The vulnerability in OpenSSL allows attackers to exploit automated decryption notifications to carry out a Bleichenbacher padding oracle attack. By sending numerous messages for decryption, attackers can recover encryption keys or decrypt RSA encrypted messages.

The Impact of CVE-2019-1563

The vulnerability could potentially lead to the decryption of sensitive information encrypted using RSA keys, posing a significant security risk.

Technical Details of CVE-2019-1563

This section provides more in-depth technical details about the vulnerability.

Vulnerability Description

The vulnerability in PKCS7_dataDecode and CMS_decrypt_set1_pkey functions of OpenSSL allows for a Padding Oracle attack, enabling decryption of encrypted messages.

Affected Systems and Versions

OpenSSL 1.1.1d (previously impacted versions 1.1.1 to 1.1.1c)
OpenSSL 1.1.0l (previously impacted versions 1.1.0 to 1.1.0k)
OpenSSL 1.0.2t (previously impacted versions 1.0.2 to 1.0.2s)

Exploitation Mechanism

Attackers exploit automated decryption notifications to recover encryption keys or decrypt RSA encrypted messages, leveraging the Bleichenbacher padding oracle attack.

Mitigation and Prevention

Protecting systems from CVE-2019-1563 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update OpenSSL to the fixed versions (1.1.1d, 1.1.0l, 1.0.2t) to mitigate the vulnerability.
Monitor for any unusual decryption activities that could indicate exploitation.

Long-Term Security Practices

Implement secure encryption practices to minimize the impact of decryption vulnerabilities.
Regularly update and patch OpenSSL to address security flaws.

Patching and Updates

Ensure timely application of security patches and updates provided by OpenSSL to prevent exploitation of known vulnerabilities.