A Lucky Thirteen attack is a cryptographic

timing attack In cryptography, a timing attack is a side-channel attack in which the attacker attempts to compromise a cryptosystem by analyzing the time taken to execute cryptographic algorithms. Every logical operation in a computer takes time to execute, an ...

against implementations of the

Transport Layer Security Transport Layer Security (TLS) is a cryptographic protocol designed to provide communications security over a computer network, such as the Internet. The protocol is widely used in applications such as email, instant messaging, and voice over ...

(TLS) protocol that use the

CBC CBC may refer to: Media * Cadena Baja California or Grupo Cadena, a radio and television broadcaster in Mexico * Canadian Broadcasting Corporation, Canada's radio and television public broadcaster ** CBC Television ** CBC Radio One ** CBC Music ** ...

mode of operation, first reported in February 2013 by its developers Nadhem J. AlFardan and Kenny Paterson of the Information Security Group at

Royal Holloway, University of London Royal Holloway, University of London (RH), formally incorporated as Royal Holloway and Bedford New College, is a public university, public research university and a constituent college, member institution of the federal University of London. It ...

. Includes list of which software versions are vulnerable.

Attack

It is a new variant of Serge Vaudenay's

padding oracle attack In cryptography, a padding oracle attack is an attack which uses the padding validation of a cryptographic message to decrypt the ciphertext. In cryptography, variable-length plaintext messages often have to be padded (expanded) to be compatible ...

that was previously thought to have been fixed, that uses a

timing side-channel attack In cryptography, a timing attack is a side-channel attack in which the attacker attempts to compromise a cryptosystem by analyzing the time taken to execute cryptographic algorithms. Every logical operation in a computer takes time to execute, an ...

against the

message authentication code In cryptography, a message authentication code (MAC), sometimes known as an authentication tag, is a short piece of information used for authentication, authenticating and Data integrity, integrity-checking a message. In other words, it is used t ...

(MAC) check stage in the TLS algorithm to break the algorithm in a way that was not fixed by previous attempts to mitigate Vaudenay's attack.

"In this sense, the attacks do not pose a significant danger to ordinary users of TLS in their current form. However, it is a truism that attacks only get better with time, and we cannot anticipate what improvements to our attacks, or entirely new attacks, may yet be discovered." — Nadhem J. AlFardan and Kenny Paterson

The researchers only examined Free Software implementations of TLS and found all examined products to be potentially vulnerable to the attack. They have tested their attacks successfully against OpenSSL and GnuTLS. Because the researchers applied

responsible disclosure In computer security, coordinated vulnerability disclosure (CVD, sometimes known as responsible disclosure) is a vulnerability disclosure model in which a vulnerability or an issue is disclosed to the public only after the responsible parties hav ...

and worked with the software vendors, some software updates to mitigate the attacks were available at the time of publication. Martin R. Albrecht and Paterson have since demonstrated a variant Lucky Thirteen attack against Amazon's

s2n s2n-tls, originally named s2n, is an open-source C99 implementation of the Transport Layer Security (TLS) protocol developed by Amazon Web Services (AWS) and initially released in 2015. The goal was to make the code—about 6,000 lines long—ea ...

TLS implementation, even though s2n includes countermeasures intended to prevent timing attacks.

References

External links

Time is money (in CBC ciphersuites)
Nikos Mavrogiannopoulos, 5 February 2013 Cryptographic attacks Side-channel attacks 2013 in computing Transport Layer Security {{crypto-stub

Attack

See also

References

External links