Displaying 20 results from an estimated 6000 matches similar to: "ssh_dh?"
2018 Dec 17
0
ssh_dh?
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On 17 December 2018 at 00:30 Daniel Miller via dovecot <
<a href="mailto:dovecot@dovecot.org">dovecot@dovecot.org</a>> wrote:
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2020 May 24
1
A small mistake in a Dovecot error message.
I'm setting up a new mail server and got this message:
May 21 11:55:09 vader dovecot[4090]: imap-login: Error: Diffie-Hellman key exchange requested, but no DH parameters provided.
Set ssh_dh=</path/to/dh.pem
The Dovecot parameter is actually: ss*l*_dh<=/path/to/dh.pem not ssh...
Fedora release 32 (Thirty Two)
dovecot-2.3.9.3-1.fc32.x86_64
Many thanks for such useful software.
Bill
2007 Sep 21
4
Diffie Hellman key exchange algorithms
A few questions regarding the OpenSSH support for the Diffie Hellman key exchange algorithms:
(1) Are the diffie-hellman-group-exchange-sha256",
"diffie-hellman-group-exchange-sha1"
, "diffie-hellman-group14-sha1" "diffie-hellman-group1-sha1" (as
defined in RFCs 4253 and RFC 4419) the complete list of key exchange
algorithms supported by OpenSSH?
(2) Is there a
2019 Jan 19
4
Can we disable diffie-hellman-group14-sha1 by default?
I'm not sure if collision resistance is required for DH key
derivation, but generally, SHA-1 is on its way out. If it's possible
(if there's not a very large percentage of servers that do not support
anything newer), it should be disabled.
2015 May 21
8
Weak DH primes and openssh
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
2017 Sep 24
3
DH Group Exchange Fallback
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
2015 Jul 24
2
DH_GRP_MIN is currently 1024, should it be bumped to 2048?
Greetings,
Given the weakness with Diffie-Hellman modp groups less than 2048, is it
time to bump the suggested 1024 bit minimum value from the RFC 4419 to a
more current 2048 value for OpenSSH 7.0?
If so, should this be just a compile-time change, or should there be a
new client and server runtime option?
Thanks,
-- Mark
2017 Sep 23
2
DH Group Exchange Fallback
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
2003 Jun 05
2
Slow connection performance - ssh2
Using ssh2 via agent to connect through proxy to sshd host. Each
connection (client to proxy, proxy to host) takes an average of 22
seconds, totaling approximately 44 seconds for a complete connection.
Debug logging with vmstat directed to the same file indicates two points
where a majority of time is spent (have looked at the similar postings):
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP (*6
2024 Jan 26
1
enable strong KexAlgorithms, Ciphers and MACs in /etc/ssh/sshd_config file on RHEL 8.x Linux OS
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
2019 Mar 16
3
ssl_dh
https://wiki.dovecot.org/SSL/DovecotConfiguration says:
"Since v2.3.3+ Diffie-Hellman parameters have been made optional, and
you are encouraged to disable non-ECC DH algorithms completely."
and a bit later:
"From version 2.3, you must specify path to DH parameters file using
ssl_dh=</path/to/dh.pem"
So.
1. Is ssl_dh an optional or a must?
2. I've disabled ssl_dh
2013 Sep 24
3
2048-bit Diffie-Hellman parameters
Currently, dovecot generates two primes for Diffie-Hellman key
exchanges: a 512-bit one and a 1024-bit one. In light of recent
events, I think it would be wise to add support for 2048-bit primes as
well, or even better, add a configuration option that lets the user
select a file (or files) containing the DH parameters
In recent years, there has been increased interest in DH especially in
its
2017 Sep 22
6
DH Group Exchange Fallback
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
2014 Mar 07
12
[Bug 2209] New: Problem logging into Cisco devices under 6.5p1 (kexgexc.c)
https://bugzilla.mindrot.org/show_bug.cgi?id=2209
Bug ID: 2209
Summary: Problem logging into Cisco devices under 6.5p1
(kexgexc.c)
Product: Portable OpenSSH
Version: 6.5p1
Hardware: amd64
OS: FreeBSD
Status: NEW
Severity: normal
Priority: P5
Component: ssh
2006 Apr 07
1
your mail
> On Thu, 6 Apr 2006, Miller, Damien wrote:
>
> >
> > Does OpenSSH 4.3 support the use of the TLS ciphersuites that are
> > supported in OpenSSL?
> > If so, is this a compile time option or a run-time option?
> Or can sshd
> > support both the SSL and TLS ciphersuites at the same time?
>
> OpenSSH doesn't use SSL or TLS - the SSH protocol
2014 Oct 28
22
[Bug 2302] New: ssh (and sshd) should not fall back to deselected KEX algos
https://bugzilla.mindrot.org/show_bug.cgi?id=2302
Bug ID: 2302
Summary: ssh (and sshd) should not fall back to deselected KEX
algos
Product: Portable OpenSSH
Version: 6.7p1
Hardware: All
OS: All
Status: NEW
Severity: security
Priority: P5
Component: ssh
2014 Oct 28
22
[Bug 2302] New: ssh (and sshd) should not fall back to deselected KEX algos
https://bugzilla.mindrot.org/show_bug.cgi?id=2302
Bug ID: 2302
Summary: ssh (and sshd) should not fall back to deselected KEX
algos
Product: Portable OpenSSH
Version: 6.7p1
Hardware: All
OS: All
Status: NEW
Severity: security
Priority: P5
Component: ssh
2015 Jun 02
1
[Bug 2302] with DH-GEX, ssh (and sshd) should not fall back to unconfigured DH groups or at least document this behaviour and use a stronger group
https://bugzilla.mindrot.org/show_bug.cgi?id=2302
--- Comment #13 from Darren Tucker <dtucker at zip.com.au> ---
(In reply to Christoph Anton Mitterer from comment #10)
[...]
> Even though an attacker cannot (AFAIU??) for a connection to
> downgrade to the weaker groups,
The server's DH-GEX exchange hash includes the DH group sizes it
received from the client. If these are
2001 Apr 03
2
the "primes" file
In message <Pine.LNX.4.30.0104031615270.8678-100000 at holly.crl.go.jp>, Tom Holro
yd writes:
>SRP has different requirements from Diffie-Hellman. In particular,
>for SRP the generator must be primitive. It turns out that the "primes"
>file contains only safe primes with primitive generators, and is thus
>ideal for SRP, but so far in OpenSSH it has only been used for
2017 Sep 21
5
DH Group Exchange Fallback
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