Cache Attacks in TLS - CVE-2018-16869
Published: December 4, 2018 / Updated: February 11, 2019
Vulnerability identifier: #VU16222
CSH Severity: Medium
CVSS v4: 8.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2018-16869
CWE-ID: CWE-300
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to perform a downgrade attack on the server and decrypt private keys on the target system.
The vulnerability exists due to a core weakness in TLS that relates to the handshaking of the session key which is used within the tunnel during parallelisation of thousands of oracle queries that occurs using a cluster of TLS servers which share the same public key certificate. A remote attacker can mount a microarchitectural side channel attack against a vulnerable implementation, obtain a network man-in-the-middle position, obtain the relevant data to sign and trigger the victim server to decrypt ciphertexts chosen by the adversary to perform a downgrade attack.
The vulnerability exists due to a core weakness in TLS that relates to the handshaking of the session key which is used within the tunnel during parallelisation of thousands of oracle queries that occurs using a cluster of TLS servers which share the same public key certificate. A remote attacker can mount a microarchitectural side channel attack against a vulnerable implementation, obtain a network man-in-the-middle position, obtain the relevant data to sign and trigger the victim server to decrypt ciphertexts chosen by the adversary to perform a downgrade attack.
Affected software
TLS
cflinuxfs3
Slackware Linux
Opensuse
Ubuntu
Fedora
libnettle6 (Ubuntu package)
nettle
mingw-nettle
libnettle7 (Ubuntu package)
libnettle8 (Ubuntu package)
cflinuxfs3
Slackware Linux
Opensuse
Ubuntu
Fedora
libnettle6 (Ubuntu package)
nettle
mingw-nettle
libnettle7 (Ubuntu package)
libnettle8 (Ubuntu package)
How to mitigate CVE-2018-16869
Install update from vendor's website.
cflinuxfs3 - update to 0.244.0
libnettle6 (Ubuntu package) - update to 3.4.1-0ubuntu0.18.04.1
nettle - update to 3.4.1-1.fc28
mingw-nettle - addressed in versions 3.4.1-1.fc28, 3.4.1-1.fc29
libnettle7 (Ubuntu package) - update to 3.5.1+really3.5.1-2ubuntu0.2
libnettle8 (Ubuntu package) - addressed in versions 3.6-2ubuntu0.2, 3.7-2.1ubuntu1.1
libnettle6 (Ubuntu package) - update to 3.4.1-0ubuntu0.18.04.1
nettle - update to 3.4.1-1.fc28
mingw-nettle - addressed in versions 3.4.1-1.fc28, 3.4.1-1.fc29
libnettle7 (Ubuntu package) - update to 3.5.1+really3.5.1-2ubuntu0.2
libnettle8 (Ubuntu package) - addressed in versions 3.6-2ubuntu0.2, 3.7-2.1ubuntu1.1