Paper 2023/1711 Original: eprint.iacr.org/2023/1711 ↗
Passive SSH Key Compromise via Lattices
Abstract
We demonstrate that a passive network attacker can opportunistically obtain private RSA host keys from an SSH server that experiences a naturally arising fault during signature computation. In prior work, this was not believed to be possible for the SSH protocol because the signature included information like the shared Diffie-Hellman secret that would not be available to a passive network observer. We show that for the signature parameters commonly in use for SSH, there is an efficient lattice attack to recover the private key in case of a signature fault. We provide a security analysis of the SSH, IKEv1, and IKEv2 protocols in this scenario, and use our attack to discover hundreds of compromised keys in the wild from several independently vulnerable implementations.
Metadata
- Available format(s)
PDF- Category
- Attacks and cryptanalysis
- Publication info
- Preprint.
- History
- 2023-11-05: last updated
- 2023-11-05: published
- Short URL
- https://ia.cr/2023/1711
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2023/1711,
author = {Keegan Ryan and Kaiwen He and George Arnold Sullivan and Nadia Heninger},
title = {Passive SSH Key Compromise via Lattices},
howpublished = {Cryptology {ePrint} Archive, Paper 2023/1711},
year = {2023},
url = {https://eprint.iacr.org/2023/1711}
}