search for: terrapin

You might find RedHat's CVE page on this useful: https://access.redhat.com/security/cve/cve-2023-48795 On Tue, Jan 23, 2024 at 10:04?AM Kaushal Shriyan <kaushalshriyan at gmail.com> wrote: > Hi, > > I have the SSH Terrapin Prefix Truncation Weakness on Red Hat Enterprise > Linux release 8.7 (Ootpa). The details are as follows. > > # rpm -qa | grep openssh > openssh-8.0p1-16.el8.x86_64 > openssh-askpass-8.0p1-16.el8.x86_64 > openssh-server-8.0p1-16.el8.x86_64 > openssh-clients-8.0p1-16.el8.x86_64...

Hi, I have the SSH Terrapin Prefix Truncation Weakness on Red Hat Enterprise Linux release 8.7 (Ootpa). The details are as follows. # rpm -qa | grep openssh openssh-8.0p1-16.el8.x86_64 openssh-askpass-8.0p1-16.el8.x86_64 openssh-server-8.0p1-16.el8.x86_64 openssh-clients-8.0p1-16.el8.x86_64 # cat /etc/redhat-release Red Hat...

...w config option to make strict-kex mandatory, I also wonder if a new mechanism for ciphers/macs can be introduced and is reliable by simple both sides using it. So there could be a Chacha20-Poly1305v2 at openssh.com which uses AD data to chain the messages together, so it will be resistant against terrapin even without the strict-kex. Consequently the hmac-etmv2 at openssh.com mode could be deviced in a similar manner, to also include the transcript hash or similar things. The impact of removing the only "alternative" cipher cc20p1305 because of terrapin hardening as well as falling back...

Hi there, > So there could be a Chacha20-Poly1305v2 at openssh.com which uses AD data to chain the > messages together, so it will be resistant against terrapin even without the strict-kex. > > Consequently the hmac-etmv2 at openssh.com mode could be deviced in a similar manner, to > also include the transcript hash or similar things. This would still require both, client and server, to receive an update to support these new algorithms. So I wond...

...gers.edu comp.security.ssh posting and reply from Richard Silverman below: While trying to troubleshoot a seperate problem, I came across a strange, repeatable behavior that I haven't been able to find any further information on. In short, I'm establishing a simple port forward from 'terrapin' to 192.168.1.120 via 'osgiliath,' another host on 192.168.1.0/24. An Nmap of the port I'm forwarding on the local machine causes the SSH session to end. To establish the connection, I issue the following command: -- terrapin:~ irish$ ssh -vvv -L 3389:192.168.1.120:3389 irish at o...

...ailable since OpenSSH 7.2 (key) rsa-sha2-256 (4096-bit) -- [info] available since OpenSSH 7.2 (key) ssh-ed25519 -- [info] available since OpenSSH 6.5 # encryption algorithms (ciphers) (enc) chacha20-poly1305 at openssh.com -- [warn] vulnerable to the Terrapin attack (CVE-2023-48795), allowing message prefix truncation (enc) chacha20-poly1305 at openssh.com -- [info] available since OpenSSH 6.5 (enc) chacha20-poly1305 at openssh.com -- [info] default cipher since OpenSSH 6.9 (enc) aes256-gcm at openssh.com -- [info] availab...

On 25.01.24 14:09, Kaushal Shriyan wrote: > I am running the below servers on Red Hat Enterprise Linux release 8.7 > How do I enable strong KexAlgorithms, Ciphers and MACs On RHEL 8, you need to be aware that there are "crypto policies" modifying sshd's behaviour, and it would likely be the *preferred* method to inject your intended config changes *there* (unless they

...ed weakness in the SSH transport protocol, a logic error relating to constrained PKCS#11 keys in ssh-agent(1) and countermeasures for programs that invoke ssh(1) with user or hostnames containing invalid characters. * ssh(1), sshd(8): implement protocol extensions to thwart the so-called "Terrapin attack" discovered by Fabian B??umer, Marcus Brinkmann and J??rg Schwenk. This attack allows a MITM to effect a limited break of the integrity of the early encrypted SSH transport protocol by sending extra messages prior to the commencement of encryption, and deleting an equal numb...

...ed weakness in the SSH transport protocol, a logic error relating to constrained PKCS#11 keys in ssh-agent(1) and countermeasures for programs that invoke ssh(1) with user or hostnames containing invalid characters. * ssh(1), sshd(8): implement protocol extensions to thwart the so-called "Terrapin attack" discovered by Fabian B??umer, Marcus Brinkmann and J??rg Schwenk. This attack allows a MITM to effect a limited break of the integrity of the early encrypted SSH transport protocol by sending extra messages prior to the commencement of encryption, and deleting an equal numb...

Hi Kaushal, I maintain a set of SSH hardening guides for various platforms, including RHEL 8. You can find them here: https://ssh-audit.com/hardening_guides.html - Joe -- Joseph S. Testa II Founder & Principal Security Consultant Positron Security On Thu, 2024-01-25 at 18:39 +0530, Kaushal Shriyan wrote: > Hi, > > I am running the below servers on Red Hat Enterprise

Hello, since one currently (after the 9.6 release addressing terrapin with strict-kex) cant be sure that strict KEX mode is negotiated (it depends on the capabilities of the partner), and the mitigation for that is to disable most modern/alternative ciphers and MAC modes - I would suggest you offer the option to enforce strict-kex mode as a server config as well as...