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A comment on Terrapin Attack for prefix truncation in SSH. Parent comment

Re:Terrapin Attack for prefix truncation in SSH by Skrillor on Monday December 18, 2023 @02:58PM (#38687365)
We updated the FAQ question to cover this. For most users, fixing can be done by installing patched versions of their SSH implementations as they come available. If you feel uncomfortable waiting for an update, you may disable the affected cipher modes temporarily and use other modes like AES-GCM instead. But keep in mind that a faulty configuration can cause you to loose access to the server.
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Re:Terrapin Attack for prefix truncation in SSH by colmmacc on Monday December 18, 2023 @03:03PM (#38687435)
Fwiw, I found a bunch of clients and libraries that didn't support AES-GCM at all, or only very recently. libssh2 is one example. That's made me nervous to make AES-GCM the only supported cipher as a mitigation.
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Re:Terrapin Attack for prefix truncation in SSH by Aloisius on Monday December 18, 2023 @03:31PM (#38687773)
What about aes-ctr?
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Re:Terrapin Attack for prefix truncation in SSH by lambdafu on Monday December 18, 2023 @04:58PM (#38688941)
Depends a bit on the MAC. CTR-EtM is technically vulnerable (i.e. cryptographically broken), but due to key stream desynchronization the attack will quickly lead to application errors, defeating the attacker. See Sect. 4.3.3.
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Re:Terrapin Attack for prefix truncation in SSH by shaicoleman on Monday December 18, 2023 @08:01PM (#38690503)
FYI: libssh2 supports AES-GCM since 1.11.0 (released 2023-05-30)
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