similar to: [Bug 769] dh-group-exchange should be configurable off in client and server

http://bugzilla.mindrot.org/show_bug.cgi?id=769 Summary: dh-group-exchange should be configurable off in client and server Product: Portable OpenSSH Version: 3.7p1 Platform: All OS/Version: All Status: NEW Severity: enhancement Priority: P2 Component: ssh AssignedTo:

http://bugzilla.mindrot.org/show_bug.cgi?id=697 Summary: ending slash is not used Product: Portable OpenSSH Version: 3.7.1p1 Platform: PPC OS/Version: AIX Status: NEW Severity: normal Priority: P2 Component: sftp-server AssignedTo: openssh-bugs at mindrot.org ReportedBy: ramses at

Hi, I'm interested in requiring a minimum of 3072-bit DH moduli when using the "diffie-hellman-group-exchange-sha256" kex, so I edited my /etc/ssh/moduli file such that only 3071+ moduli are left. However, when clients ask for a max of 2048-bit moduli, they actually get one (!). I poked around and found that a fallback mechanism exists (dh.c:185), which returns back the

On 09/24/2017 12:21 AM, Mark D. Baushke wrote: > I suggest you upgrade to a more recent edition of the OpenSSH software. > The most recent release is OpenSSH 7.5 and OpenSSH 7.6 will be released > very soon. This problem is in v7.5 and v7.6. See dh.c:436. > OpenSSH 6.6 was first released on October 6, 2014. I brought up v6.6 to give an example that older clients wouldn't be

http://bugzilla.mindrot.org/show_bug.cgi?id=1291 Summary: aes256-ctr, aes192-ctr, arcfour256 broken with OpenSSL 0.9.8e Product: Portable OpenSSH Version: 4.5p1 Platform: All OS/Version: All Status: NEW Severity: minor Priority: P2 Component: sshd AssignedTo: bitbucket at

On 09/22/2017 06:10 PM, Mark D. Baushke wrote: > I suppose you want to be more paranoid: > > DH * > dh_new_group_fallback(int max) > { > debug3("%s: requested max size %d", __func__, max); > if (max <= 2048) { > debug3("using 2k bit group 14"); > return dh_new_group14(); > }

http://bugzilla.mindrot.org/show_bug.cgi?id=1025 Summary: Does not correctly send/parse disabled special character in ttymodes Product: Portable OpenSSH Version: 4.0p1 Platform: All OS/Version: All Status: NEW Severity: normal Priority: P2 Component: sshd AssignedTo:

On 09/22/2017 06:55 PM, Tim Broberg wrote: > Do I understand correctly, that you find the security of group 14 unacceptable and yet you left it enabled? In the end, I'm trying to ensure a minimum equivalent of 128-bits of security. Group14 is 2048-bits, which roughly translates to 112-bits. [1] To this end, I disabled the "diffie-hellman-group14-sha1" and

On Fri 2015-05-22 00:06:29 -0400, Darren Tucker wrote: > On Thu, May 21, 2015 at 11:26 PM, Matthew Vernon <matthew at debian.org> wrote: >> >> You will be aware of https://weakdh.org/ by now, I presume; the >> take-home seems to be that 1024-bit DH primes might well be too weak. >> I'm wondering what (if anything!) you propose to do about this issue, >>

On 09/22/2017 03:22 PM, Daniel Kahn Gillmor wrote: > On Thu 2017-09-21 18:12:44 -0400, Joseph S Testa II wrote: >> I gotta say... having a fallback mechanism here seems pretty >> strange. The entire point of the group exchange is to use a dynamic >> group and not a static one. > > fwiw, i think dynamic groups for DHE key exchange is intrinsically > problematic

> Can this be addressed in ssh_config/sshd_config with the KexAlgorithms setting? weakdh.org/sysadmin.html recommends adding: KexAlgorithms curve25519-sha256 at libssh.org But this thread makes it sound as if it's not necessary. Can anyone confirm? Personally I'm on openssh-6.7. - Grant > You will be aware of https://weakdh.org/ by now, I presume; the take-home seems to be

On Fri, 2019-02-15 at 15:57 +1100, Darren Tucker wrote: > That was the original intent (and it's mentioned in RFC4419) however > each moduli file we ship (70-80 instances of 6 sizes) takes about 1 > cpu-month to generate on a lowish-power x86-64 machine. Most of it > is > parallelizable, but even then it'd likely take a few hours to > generate > one of each size. I

Hi, You will be aware of https://weakdh.org/ by now, I presume; the take-home seems to be that 1024-bit DH primes might well be too weak. I'm wondering what (if anything!) you propose to do about this issue, and what Debian might do for our users? openssh already prefers ECDH, which must reduce the impact somewhat, although the main Windows client (PuTTY) doesn't support ECDH yet. But

On Tue 2015-05-26 12:57:05 -0400, Hubert Kario wrote: > creating composites that will pass even 100000 rounds of Miller-Rabin is > relatively simple.... > (assuming the values for M-R tests are picked randomly) Can you point me to the algorithms for doing that? This would suggest that we really do want primality proofs (and a good way to verify them). Do those algorithms hold for

https://bugzilla.mindrot.org/show_bug.cgi?id=2303 Bug ID: 2303 Summary: ssh (and perhaps even sshd) should allow to specify the minimum DH group sizes for DH GEX Product: Portable OpenSSH Version: 6.7p1 Hardware: All OS: All Status: NEW Severity: security Priority: P5

On Tue 2015-05-26 14:02:07 -0400, Hubert Kario wrote: > On Tuesday 26 May 2015 13:43:13 Daniel Kahn Gillmor wrote: >> On Tue 2015-05-26 12:57:05 -0400, Hubert Kario wrote: >> > creating composites that will pass even 100000 rounds of Miller-Rabin is >> > relatively simple.... >> > (assuming the values for M-R tests are picked randomly) >> >> Can you

I'm not nearly knowledgeable enough in crypto to fully understand your answer, but I will try. I wonder why moduli are not automatically generated the first time sshd is started though. That would make much more sense than shipping a default moduli file but also asking everyone to replace it with their own. On Fri, Feb 15, 2019 at 5:50 AM Mark D. Baushke <mdb at juniper.net> wrote: >

Hi, my question is related to the kex algorithm diffie-hellman-group-exchange-sha256 and moduli generation. I've seen that through ssh-keygen, I'm able to re-generate my moduli file used by DH but I'm note sure to understand one point in the ssh-keygen manpage : "Screened DH groups may be installed in /etc/ssh/moduli. It is important that this file contains moduli of a range of

I don't think there is any point to generate so many moduli. Actually, 3 moduli of sizes 2048, 3072 and 4096 seem like a sane choice. On Fri, Feb 15, 2019 at 7:58 AM Darren Tucker <dtucker at dtucker.net> wrote: > > On Fri, 15 Feb 2019 at 14:22, Yegor Ievlev <koops1997 at gmail.com> wrote: > > I'm not nearly knowledgeable enough in crypto to fully understand your

Hi, There are several programs that will basically take the outputs of your scans and store the results in a database. If you size the database appropriately, then querying that database will be much quicker than querying the filesystem. But of course the results will be a little bit outdated. One such project is robinhood. https://github.com/cea-hpc/robinhood/wiki A simpler way might be to