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Steve92Participant
Hello,
Thanks a lot for these precise infos.
I have to make a RFI (before POC) on 2 or 3 solutions of remote desktop for sensitive and complex environments.
Security is indeed a major point of the evaluation.
So ANSSI (French National Cyber Security Agency) recommendations must be taken into account in our case.
Sources: in compliance with IETF publications
2020 FRENCH https://cyber.gouv.fr/publications/recommandations-de-securite-relatives-tls
2017 ENGLISH (quite old!) https://cyber.gouv.fr/en/publications/security-recommendations-tls
In a nutshell :
*** NOT RECOMMENDED ***
ec_point_formats (0x000B) [57]
This extension reports the elliptic curve point formats supported by the client or server (if any). It is indeed possible to represent elliptic curve points in a compressed form. In the absence of this extension, it is expected that the point coordinates are transmitted in their entirety. The use of this extension has been made obsolete by the IETF, indicating that only the uncompressed format should be supported [73].
[57] S. Blake-Wilson, N. Bolyard, V. Gupta, C. Hawk et B. Moeller, « Elliptic Curve Cryptography (ECC) Cipher Suites for Transport Layer Security (TLS) », RFC 4492, IETF, May 2006.
[73] Y. Nir, S. Josefsson et M. Pegourie-Gonnard, « Elliptic Curve Cryptography (ECC) Cipher Suites for Transport Layer Security (TLS) Versions 1.2 and Earlier », RFC 8422, IETF, August 2018.
*** GENERAL RECOMMENDATION ***
signed_certificate_timestamp, ou sct (0x0012) [23]
Only if SCT.
[23] B. Laurie, A. Langley et E. Kasper, « Certificate Transparency », RFC 6962, IETF, June 2013.
*** RECOMMENDATIONS for TLS V1.2 ***
renegotiation_info (0xFF01) [60]
The renegotiation mechanism originally designed for TLS versions less than or equal to 1.2 exposes the client to a protocol vulnerability. It is indeed possible for an attacker to pass off a client’s first negotiation as a renegotiation. The attacker is thus in a position to inject application data that the server attributes to the legitimate client. The renegotiation_info extension was defined in order to perform secure renegotiations. Using this extension requires preserving the protected content of the Finished messages used to authenticate the last handshake.
[60] E. Rescorla, M. Ray, S. Dispensa et N. Oskov, « Transport Layer Security (TLS) Renegotiation Indication Extension », RFC 5746, IETF, February 2010.
Other specific cases are considered in the document (the more recent one is in French only).
Regards,
Steve.
Steve92ParticipantHello,
Thanks for this quick answer.
So the the article is up-to-date until you validate TLS 1.3.
“…the move to TLS 1.3 is something we are already working on, as low priority” means it could be available in about 6, 12 months, …more?
According to our National Cyber Security Agency, TLS 1.3 is highly recommended but TLS 1.2 is still acceptable, only if right extensions are contained in ClientHello at the beginning of a session.
Please could you give me the list of TLS extensions used in ClientHello by NoMachine ?
Thanks !
Steve.
Steve92ParticipantHello,
I read the last releases of NoMachine (>=8.12.12, July 2024) includes OpenSSL v3.0 that supports TLS 1.3 (in fact supported since OpenSSL v1.1.1).
Why TLS 1.3 could not be used ?
This page seems to be out of date:
NoMachine – Encryption In NoMachine – Knowledge Base
Could you clarify this ?
Thanks !
Steve.
Steve92ParticipantHello,
It’s a pity that NX encryption can’t be disabled when using a VPN or SSH tunnel !
Double encryption is totally useless, isn’it ?
Wasn’t it possible with older verion (if I well remember) ? Why did you remove this feature ?
Regards,
Steve.
Steve92ParticipantHello,
After many hours of research on the Web, I finally found this solution, at display manager level, to get “azerty” (french) keyboard when login to Debian 10:
– edit /etc/lightdm/lightdm.conf
– under the section [Seat:*] add:
display-setup-script=setxkbmap fr#Free bonus ! 🙂
To get an ‘azerty’ keyboard after Debian login
in /etc/xdg/lxsession/LXDE/autostart
add: setxkbmap -layout “fr,fr”It seems so simple once you have the solution. :o)
I hope it will help all people who need “azerty” keyboard ! 😉
Regards,
Steve.
Steve92ParticipantHello,
Here is what I get in log: strange error when try to clean a non empty directory ?!?
1st test : login via VPN installed on VPS I access, session logout takes about 30 s. !!!
— Access via VPN —————-
2020-10-22 22:18:11 565.410 14422 NXSERVER User ‘root’ logged in from ‘10.8.0.2’ using authentication method NX-password.
2020-10-22 22:18:40 237.188 987 NXNODE WARNING! Process ‘/usr/NX/bin/nxexec /usr/NX/scripts/restricted/nxamixer.sh mute 0 0’ with pid ‘14657/14657’ finished with exit code 1 after 0,152 seconds.
2020-10-22 22:19:16 814.560 987 NXNODE ERROR! Session monitor: cleaning session files: cannot remove directory /usr/NX/var/log/node/C-vps999999-1001-3886D41748462B75D97C47F5B114F626/devices: Directory not empty
2020-10-22 22:19:16 815.297 987 NXNODE ERROR! session monitor: cleaning session files: cannot remove dir ‘/usr/NX/var/log/node/C-vps999999-1001-3886D41748462B75D97C47F5B114F626’: Directory not empty
2020-10-22 22:21:10 156.495 14422 NXSERVER User ‘root’ from ‘10.8.0.2’ logged out.
2020-10-22 22:21:10 244.216 15532 NXNODE WARNING! Process ‘/usr/NX/bin/nxexec /usr/NX/scripts/restricted/nxamixer.sh mute 0 0’ with pid ‘15732/15732’ finished with exit code 1 after 0,061 seconds.2nd test: login via SSH tunnel with VPS I access, session logout takes about 15 s. !
— Access via SSH tunnel ——————–
2020-10-22 22:33:41 960.230 17150 NXSERVER User ‘root’ logged in from ‘151.12.34.56’ using authentication method NX-password.
2020-10-22 22:34:18 522.887 15532 NXNODE ERROR! Session monitor: cleaning session files: cannot remove directory /usr/NX/var/log/node/C-vps999999-1001-28C1704048563D930A1BBAB070D0BEAA/devices: Directory not empty
2020-10-22 22:34:18 523.125 15532 NXNODE ERROR! session monitor: cleaning session files: cannot remove dir ‘/usr/NX/var/log/node/C-vps999999-1001-28C1704048563D930A1BBAB070D0BEAA’: Directory not empty
2020-10-22 22:39:07 684.815 17150 NXSERVER User ‘root’ from ‘151.12.34.56’ logged out.
2020-10-22 22:39:07 720.752 18464 NXNODE WARNING! Process ‘/usr/NX/bin/nxexec /usr/NX/scripts/restricted/nxamixer.sh mute 0 0’ with pid ‘18621/18621’ finished with exit code 1 after 0,046 seconds.————————-
Could these errors explain the long delay to logout ?
How to solve them ?
Thanks,
Regards,
Steve.
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