CVE-2023-48795 is a prefix truncation attack affecting the SSH protocol. The attack can be achieved on ChaCha20-Poly1305 or any cipher relying on the CBC mode with an encrypt-then-mac approach. The issue is mitigated in recent OpenSSH versions but the underlying protocol issue is still here. Removing ChaCha20-Poly1305 from the list of usable ciphers we set is enough to be fix the the issue. The list of MACs has also been cleaned up to keep only sane January 2024 possibilities (and be conform to Enalean internal crypto policy). No functional changes expected, all the ciphers and MACs we set are widespread and present in OpenSSH since a long time. The AES ciphers using the CTR mode should ideally be removed but I'm a bit concerned by the fact it might some SSH clients. This should likely be revisited in a few months. The "Terrapin" attack is theoretically applicable to these CTR mode ciphers but it cannot really be exploited. Change-Id: Id6835b862a0ded50fbc7be81003817aa7f418021

+4 −4

Author

Thomas Gerbet (tgerbet) 2024-01-23 11:08

Committer

Thomas Gerbet (tgerbet) 2024-01-23 11:08

Hash 5b57717bc32ed57a13135890e0d602f83b4101a0

Parent 7183cfee97a082117a06876d2df04d0733fbd4c7

Reference git #tuleap/stable/5b57717bc32ed57a13135890e0d602f83b4101a0