Better docs for DisableTrivialAuth

This commit is contained in:
Matt Johnston 2022-11-11 11:25:50 +08:00
parent 960d374e65
commit b2b94acc97
2 changed files with 27 additions and 6 deletions

13
CHANGES
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@ -40,7 +40,7 @@ Features and Changes:
- Improve permission error message
Patch from k-kurematsu
2022.82 regression fixes:
Regression fixes from 2022.82:
- Fix X11 build
@ -155,10 +155,13 @@ Features and Changes:
Patch from Raphaël Hertzog
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=903403
- Added client option "-o DisableTrivialAuth". This can be used to prevent
the server immediately accepting successful authentication (before any auth
request) which could cause UI confusion and security issues with agent
forwarding - it isn't clear which host is prompting to use a key.
- Added client option "-o DisableTrivialAuth". It disallows a server immediately
giving successful authentication (without presenting any password/pubkey prompt).
This avoids a UI confusion issue where it may appear that the user is accepting
a SSH agent prompt from their local machine, but are actually accepting a prompt
sent immediately by the remote server.
CVE-2021-36369 though the description there is a bit confused. It only applies
to Dropbear as a client.
Thanks to Manfred Kaiser from Austrian MilCERT
- Add -q client option to hide remote banner, from Hans Harder

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@ -94,7 +94,18 @@ is performed at all, this is usually undesirable.
.B \-A
Forward agent connections to the remote host. dbclient will use any
OpenSSH-style agent program if available ($SSH_AUTH_SOCK will be set) for
public key authentication. Forwarding is only enabled if -A is specified.
public key authentication. Forwarding is only enabled if \fI-A\fR is specified.
Beware that a forwarded agent connection will allow the remote server to have
the same authentication credentials as you have used locally. A compromised
remote server could use that to log in to other servers.
In many situations Dropbear's multi-hop mode is a better and more secure alternative
to agent forwarding, avoiding having to trust the intermediate server.
If the SSH agent program is set to prompt when a key is used, the
\fI-o DisableTrivialAuth\fR option can prevent UI confusion.
.TP
.B \-W \fIwindowsize
Specify the per-channel receive window buffer size. Increasing this
@ -159,6 +170,13 @@ Send dbclient log messages to syslog in addition to stderr.
.TP
.B Port
Specify a listening port, like the \fI-p\fR argument.
.TP
.B DisableTrivialAuth
Disallow a server immediately
giving successful authentication (without presenting any password/pubkey prompt).
This avoids a UI confusion issue where it may appear that the user is accepting
a SSH agent prompt from their local machine, but are actually accepting a prompt
sent immediately by the remote server.
.RE
.TP
.B \-s