This new attack is also functional against the recently released TLS 1.3 protocol
A new cryptographic attack capable of
disrupting the encrypted Transport
Layer Security (TLS) traffic has been discovered; according to network
security and ethical hacking specialists from the International Institute of
Cyber Security, this could allow threat actors to intercept and extract data
transported by a method that was considered secure.
This new attack variant is functional even
against TLS 1.3, the latest version of the security protocol, launched during
the second quarter of 2018. The attack is not entirely new, the experts pointed
out; it is a variant of a known attack, specifically the Bleichenbacher attack.
According to specialists in network
security, the original attack was named because of Daniel
Bleichenbacher, an expert in cryptography, who in 1998 made the first variant
of attacks against systems using RSA encryption together with the function of
PKCS # 1 V1 encryption. Since then, multiple variants of the attack have been developed
by various experts.
The main reason for the emergence of so many
variants of the Bleichenbacher attack is that the TLS security protocol authors
opted to add protection measures to make it more difficult to guess the RSA
encryption key, rather than replacing this algorithm with a whole new
development. These measures were defined in the 18.104.22.168 section of the TLS
standard, but since their publication there are plenty of hardware and software
developers who do not implement them as dictated by the protocol.
According to network security experts, the
implementation flaws of these security measures have caused countless servers,
firewalls, routers, VPN, and code libraries supporting TS to still be
vulnerable to some variants of the Bleichenbacher attack.
A new way to break RSA PKCS#1 v1 (the most used
RSA configuration for encrypting TLS connections) was recently discovered and, as
if this was not enough, this new Bleichenbacher attack variant is also
functional in QUIC, the new encryption protocol for Google.
“The attack takes advantage of a side channel
leak through these implementations to break the RSA key exchange of TLS
deployments,” the investigators mentioned in their report. “We tested nine different TLS implementations
against cache attacks and we can confirm that 7 are vulnerable: OpenSSL, Amazon
s2n, MbedTLS, Apple CoreTLS, Mozilla NSS, WolfSSL and GnuTLS”.
The updated versions of all the affected
libraries were published simultaneously since November 2018, when the
researchers revealed the first advances of their work.
The vulnerabilities that make this new variant
of Bleichenbacher attack viable have been tracked as: CVE-2018-12404,
CVE-2018-19608, CVE-2018-16868, CVE-2018-16869 and CVE-2018-16870.