SB2020091646 - Ubuntu update for openssl
Published: September 16, 2020 Updated: April 23, 2025
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 4 secuirty vulnerabilities.
1) Raccoon attack (CVE-ID: CVE-2020-1968)
The vulnerability allows a remote attacker to gain access to potentially sensitive information.
The vulnerability exists due to a timing flaw in the TLS specification. A remote attacker can compute the pre-master secret in connections which have used a Diffie-Hellman (DH) based ciphersuite and eavesdrop on all encrypted communications sent over that TLS connection.
Note: The attack can only be exploited if an implementation re-uses a DH secret across multiple TLS connections.
2) 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.
3) Cryptographic issues (CVE-ID: CVE-2019-1551)
The vulnerability allows a remote attacker to gain access to sensitive information.
The vulnerability exists due to an overflow issue within the rsaz_512_sqr(): the x64_64 Montgomery squaring procedure used in exponentiation with 512-bit moduli. A remote attacker can perform an attack against DH512 keys.
4) 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.