c0r0n3r

Which TLS/cryptography analyzer is right for you?

Exploiting the computationally expensive nature of the Diffie-Hellman key exchange protocol an attacker can perform a denial-of-service (DoS) attack by sending arbitrary numbers as public keys to a target server forcing it to generate its public key, validate the peer's one, and compute the shared secret. All three operations require the computationally complex modular exponentiation which creates an asymmetric resource usage situation, which is the basis for overloading the server's CPU and rendering it unavailable. The attack is carried out with such a methodology called D(HE)at attack (CVE-2002-20001).

Conclusion

"The DHEat attack remains viable against most SSH installations, as default settings are inadequate at deflecting it. Very little bandwidth is needed to cause a dramatic effect on targets, including those with a high degree of resources. Hence, SSH services should be blocked from external access whenever possible. Furthermore, connection rate limiting should always be applied regardless of network segmentation, as per the central principles of Zero Trust."

We factorize a 48-bit integer using 10 trapped-ion qubits on a Quantinuum’s quantum computer. This result outperforms the recent achievement by B. Yan et al., arXiv:2212.12372 (2022), increasing the success probability by a factor of 6 with a non-hybrid digitized-counterdiabatic quantum factorization (DCQF) algorithm. We expect better results with hybrid DCQF methods on our path to factoring RSA-64, RSA-128, and RSA-2048 in this NISQ era, where the latter case may need digital-analog quantum computing (DAQC) encoding.

Chinese researchers claim that there is an existing algorithm that, even with today's quantum computers, makes it possible to break the RSA algorithm. At the same time, there are doubts about the reliability of the publication. However, even if these doubts are confirmed, it does not change the fact that quantum computers pose security threat now.

... The CVE-2002-20001 (a.k.a DHEat attack) vulnerability inherent to the support of the Diffie-Hellman (DH) and Elliptic Curve Diffie-Hellman (ECDH) key exchanges in TLS and other protocols provides a way for an attacker to cause high CPU usage on servers with relatively low effort on the client side. ...