SB2020070956 - Ubuntu update for openssl

Description

This security bulletin contains information about 3 secuirty vulnerabilities.

1) Cryptographic issues (CVE-ID: CVE-2019-1547)

The vulnerability allows a remote attacker to decrypt traffic.

The vulnerability exists due to insufficient enforcement of side channel resistant code paths. A remote attacker with ability to create a large number of signatures, where explicit parameters with no co-factor is present, can force the application to fall back to non-side channel resistant code pathsduring ECDSA signature operation and perform full key recovery.

Successful exploitation of the vulnerability may allow an attacker to decrypt communication between server and client.

2) Use of a broken or risky cryptographic algorithm (CVE-ID: CVE-2019-1559)

The vulnerability allows a remote attacker to decrypt sensitive information.

The vulnerability exists due to the way an application behaves, when it receives a 0-byte record with invalid padding compared to the record with an invalid MAC, which results in padding oracle. A remote attacker can decrypt data.

Successful exploitation of the vulnerability requires that the application is using "non-stitched" ciphersuites and calls SSL_shutdown() twice (first, via a BAD_RECORD_MAC and again via a CLOSE_NOTIFY). 

3) Padding oracle attack (CVE-ID: CVE-2019-1563)

The vulnerability allows a remote attacker to perform padding oracle attack.

The vulnerability exists due to possibility to perform a Bleichenbacher padding oracle attack against the RSA key, in situations where an attacker receives automated notification of the success or failure of a decryption attempt an attacker. A remote attacker can send a very large number of messages to be decrypted, can recover a CMS/PKCS7 transported encryption key or decrypt any RSA encrypted message that was encrypted with the public RSA key.

Remediation

Install update from vendor's website.

References

• https://ubuntu.com/security/notices/USN-4376-2