Questions tagged [authentication]

Use this tag for questions relating to authentication mechanism (i.e. proving to the system that you are you, using passwords, keycards etc.). In general don't use this and the security tag on the same question, unless it is about the security of the authentication process.

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Totally Legit Signing Key <[email protected]>

I run: gpg --list-keys I get: pub rsa1024 2014-01-26 [C] <REMOVED> uid [ unknown] Totally Legit Signing Key <[email protected]> Can this be dangerous? What is this? ...
Ohumeronen's user avatar
5 votes
1 answer
499 views

/var/log/auth.log stops recording authentication errors

As the title says, /var/log/auth.log stops recording authentication errors. It all began with I accidentally deleting it. Then I created it using touch command and changed the owner:group to syslog:...
zzzhhh's user avatar
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0 answers
28 views

Store files in ftp server, accessible only for users from authentication server via OAuth2 protocol and separately for each other

We have in company authentication server with support of OAuth 2 protocol. We are thinking about ftp repository. Could it be possible to configure ftp repository/server so that we could provide files ...
LDonSOvrfw's user avatar
0 votes
0 answers
89 views

Enable faillock on Debian 12

Can anyone tell my how to enable faillock on Debian 12? I had a look to several tutorials but nothing worked for me. This is what I get after installation - without comments. /etc/pam.d/common-account ...
chris01's user avatar
  • 561
0 votes
0 answers
34 views

Limit shellinabox users to specific accounts

Setup and target I am running a server with ssh and shellinabox and would like to restrict login via shellinabox to one specific user only. Reasoning and approach For security reasons, the main user ...
FelixJN's user avatar
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1 vote
0 answers
315 views

PAM - Disabling "check pass; user unknown" syslog messages

TLDR: We use PAM with SSHD. CentOS and Ubuntu exist in the environment. For every SSHD failure of an unknown user, it creates two messages. One of the messages doesn't provide the unknown username and ...
Top-Lunch-7931's user avatar
0 votes
0 answers
328 views

How to authenticate with password in terminal, with fprintd authentication enabled?

I enabled fingerprint authentication on my laptop running Debian 12 by following this guide: $ doas apt install fprintd libpam-fprintd $ fprintd-enroll -f right-middle-finger $ fprintd-verify $ doas ...
mkurz's user avatar
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0 answers
74 views

Postfix mail sending issue with SMTP Authentication using SASL

I have configured an SMTP server on my Ubuntu server using Postfix, and I am encountering issues with SMTP authentication. Emails sent directly through the server are successful. However, when I ...
Deepak S's user avatar
2 votes
0 answers
27 views

How to skip further PAM checking when breaking from a command (SIGINT / ctrl+c)?

I have a custom PAM setting for sudo, to use Howdy, an application using face recognition for authentication. My current /etc/pam.d/sudo looks like this: #%PAM-1.0 auth sufficient pam_unix.so ...
renyuneyun's user avatar
2 votes
1 answer
698 views

Weak MAC Algorithm(s) Supported (SSH)

I have this lines in my /etc/ssh/sshd_config file: MACs hmac-sha2-256,hmac-sha2-512,[email protected],[email protected] MACs [email protected],[email protected],-hmac-...
Shrm's user avatar
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0 answers
19 views

IWA authentication alternative on linux

Im having a windows server configured with an adfs, which is used as Idp with saml in keycloak for my application, then I'm using adfs Device authentication, so I can login to my apps using my session ...
Ayoub Beltarchi's user avatar
-1 votes
1 answer
58 views

I am trying to use the scp command to copy a directory from a local ubuntu machine to a remote ubuntu machine

The purpose of this script is to establish an SSH connection with a remote host and then use the scp command to copy the /home/desktop/Documents directory to the target directory /home/haca/desktop ...
Erick Rodriguez's user avatar
0 votes
1 answer
106 views

Would vsftpd not default to using the system username and password?

I downloaded vsftpd-3.0.5.tar.gz and successfully compiled it to generate vsftpd on computer A. Then I copied vsftpd to another computer B and created a new file called vsftpd.conf on computer A. Then,...
ABeginner's user avatar
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12 votes
3 answers
4k views

What program in Linux computes the hash of the input password when you log in?

If I understand authentication mechanism correctly, when we input the credentials in the login prompt, the hash of the password is computed and then that hash is compared with the hash stored ...
JLC's user avatar
  • 137
0 votes
1 answer
113 views

How does kpasswd change password?

When you change password via kpasswd, does it change your password that is stored on the Kerberos server, or does it change your password that is stored in the OpenLDAP server?
JLC's user avatar
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1 vote
1 answer
164 views

What is Integrated Windows Authentication and what does it mean for me?

I was looking through my Chromium browser settings and stumbled upon something called AuthServerAllowlist, which was set to the value https://*. Digging a little deeper, it looks like this is tied to ...
Silvio Mayolo's user avatar
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0 answers
132 views

PAM: Master Password

I want to create a master password that can log into any user account on a system without needing root privileges (but we can use root to create and set up the master password). In other words, I need ...
Anish G.'s user avatar
1 vote
1 answer
127 views

Error 0x80070035 browsing to samba share from Win2019 Server only

I have a samba v4.17.5 server working well, I can browse all of the shares from Win 10 clients. The clients and the samba host are members of a domain. However, when I try to browse the samba server ...
TSG's user avatar
  • 1,688
0 votes
0 answers
157 views

openSUSE Tumbleweed: facial recognition for login: howdy and PAM configuration issues

My laptop is an Acer Swift 3. It has a fingerprint sensor, but there’s no Linux driver for this one (last time I checked). So since I like Windows Hello, I decided to set up face recognition. I’m ...
Ul Tome's user avatar
  • 117
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1 answer
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sshd: Why does an exclusion via AllowUsers result in "Permission denied, please try again."

In the end this turned out to be a simple RTFM issue, but one question remains: If a user is not mentioned in AllowUsers in /etc/ssh/sshd_config, the resulting Permission denied... reply is ...
musbur's user avatar
  • 103
-2 votes
1 answer
355 views

SSH password issue

I can ssh with account 1. But with account 2, I get password denied. But I have debug log that say the password was accepted. debug1: Authentication succeeded (password). I have also included the ...
Black Frog's user avatar
0 votes
0 answers
74 views

libpam-google-authenticator failing on kubuntu 23.04 (seemingly due to polkitd)

I have used libpam-google-authenticator for several years. I always set it up to require a password + TOTP token as the password in pam. I type in my password, and then press the button on my "...
lopass's user avatar
  • 79
0 votes
0 answers
49 views

How do I login to a network which requires authentication in Metasploitable

I am running Linux metasploitable 2.6.24-16-server on VirtualBox. I want to connect to the internet but my network requires authentication for which I usually login using a browser. But, since ...
Aditya Khare's user avatar
0 votes
0 answers
213 views

gssapi-with-mic authentication from Windows to CentOS 7.9

We are a Windows shop with some CentOS servers, which we recently joined to our domain using realmd. I can successfully log into each CentOS using my domain username and password. Now, I'm trying to ...
Andrea Di Stefano's user avatar
0 votes
0 answers
69 views

Skip first pass in sasl-pam-mysql authentication

I have configured in pam.d/ an smtp configuration module like this: $ cat pam.d/smtp auth required pam_nologin.so auth sufficient pam_mysql.so config_file=/etc/mail-pam-mysql.conf ...
easy_mungo's user avatar
0 votes
0 answers
853 views

Problem with dovecot login, how can I fix failed login?

I have a terrible problem with logging into dovecot. This is my /usr/local/etc/dovecot/passdb (just one single entry with plain password): [email protected]{PLAIN}asdf:::::: When I run dovecot auth ...
LongHike's user avatar
  • 101
0 votes
1 answer
159 views

Linux Apache hybrid basic auth - ldap and .htpasswd file credentials at the same time

I have some api covered by reverse proxy. I have configured basic auth with ldap AD credentials and it works like a charm. But there are some users from external organization that don't have AD ...
karpiu's user avatar
  • 1
0 votes
1 answer
510 views

WEBMIN LDAP authentication: passwd returns "Authentication token manipulation error"

Update:jan 25 2023 I believe I have sssd and nslcd working properly I also adjusted the pam modules in webmin. I also added db to nsswitch.conf so I checks there first. As of right now I can use ...
raultechxd's user avatar
1 vote
0 answers
296 views

How to enable gpg password prompt for OAuth2 token in mutt

I am using mutt with outlook365 which has OAuth2 support. I generated an access token which is checked by the following lines in my muttrc: set imap_authenticators = "xoauth2" set ...
FluidFox's user avatar
1 vote
0 answers
81 views

Authenticating user groups with PAM in C

I am writing a program that allow certain users and user groups to not require authentication through PAM. I want to use the pam_access module but am fairly new and can't find good documentation for ...
Alex S's user avatar
  • 11
22 votes
4 answers
17k views

PasswordAuthentication no, but I can still login by password

Why can I still ssh into my Ubuntu machine using a password? This is the /etc/ssh/sshd_config file of my Ubuntu 20.04 on ovh hosting (showing only non-commented lines for brevity): Include /etc/ssh/...
koko's user avatar
  • 253
1 vote
0 answers
186 views

Why does ssh still require a password after setting up public key authentication?

I am trying to set up ssh key authentication (OpenSSH) to allow me to connect to my desktop (server / Windows 8) from my laptop (client/ Mac OS). I generated an RSA encrypted key with ssh-keygen to ...
evnobev's user avatar
  • 11
0 votes
1 answer
3k views

What does the error stty: 'standard input': Inappropriate ioctl for device Can't obtain kerberos tickets mean?

I ran the command: nohup sh -c "echo $SU_PASSWORD | /afs/cs/software/bin/reauth; python -u ~/diversity-for-predictive-success-of-meta-learning/div_src/diversity_src/experiment_mains/...
Charlie Parker's user avatar
0 votes
1 answer
701 views

How does one authenticate with a command that requires your password in linux?

I have this issue that if I run nohup in a server for some reason when I log out of the server the permissions change and it crashes. So I was recommended to run this: /afs/cs/software/bin/reauth in ...
Charlie Parker's user avatar
1 vote
1 answer
256 views

How to create a virtual FIDO U2F passkey for Chromium?

I have read in German news that soon passkeys will replace the username/password login method. I think this won't happen soon but I think the idea is great and it will come. Passkeys are little USB ...
zomega's user avatar
  • 960
1 vote
0 answers
347 views

How can I force/guide users to use 'google-authenticator' when they login without MFA?

env: Amazon Linux 2 (centos 7 custom) I recently plugged Google Authenticator into sshd, and I want every user to use it. Current Status Users can log in without MFA using private keys that I ...
Lunartist's user avatar
  • 385
2 votes
0 answers
223 views

What is the difference between these two AuthenticationMethods?

What is the difference between the following: AuthenticationMethods publickey,keyboard-interactive AuthenticationMethods publickey,keyboard-interactive:pam The man page of sshd_config says For ...
angryserver's user avatar
0 votes
1 answer
1k views

How to determine "number of concurrent sessions" for all users on a server

I am trying to determine the total number of concurrent sessions on a server to determine a good number for the maxlogins option in /etc/security/limits.conf. How is the number of sessions calculated ...
Natolio's user avatar
  • 1,222
0 votes
1 answer
268 views

How to convert kerberos user to local user in Ubuntu?

I am having issues upgrading Ubuntu distribution, as my user is authenticated with kerberos. During upgrade, kerberos packages are removed and after restart I can't login anymore. I wonder, if I can ...
Saren Tasciyan's user avatar
1 vote
1 answer
678 views

Linux - Local account, password from AD

I have users defined in AD but because of some overrides, I have to add those accounts in my local /etc/passwd. Precisely, I want to assign a user a different GID then it is defined in AD. I want to ...
Miki's user avatar
  • 31
1 vote
1 answer
204 views

SSH with multi-factor authentication

The customer requires us to setup MFA for SSH sessions. I have successfully tested MFA using Google Authenticator by following this article: https://www.linode.com/docs/guides/how-to-use-one-time-...
supmethods's user avatar
0 votes
0 answers
135 views

Unable to connect to rainloop

I am installing Rain Loop but when I want to connect to an account I have this message that appears "Authentication failed" have you ever seen this problem
LucasGr12's user avatar
1 vote
0 answers
790 views

No Authentication Agent Found Although Already Running

I have an Alpine-Linux based system (PostmarketOS) running with the LXQT DE. Ever since I set up the system, out of the box it came with a bunch of problems with user authentication. I have various ...
Hexyl Cinnamal's user avatar
0 votes
0 answers
551 views

`wget`: Cookies doesn't authenticate

I got some cookies from my browser where I'm well authenticated into a website. I've tried to give them to wget and make it download some internal pages, but all it downloads is authentication page ...
aac's user avatar
  • 55
0 votes
1 answer
771 views

Server still ask for password after ssh-copy-id

I copied my SSH public key to a server using ssh-copy-id, but the server still ask for a password. I checked the permission on the files in the ssh folder and they are readable for user only. I also ...
omerk's user avatar
  • 1
1 vote
0 answers
200 views

dovecot: Force TCP socket disconnect on imap login failure?

I'm running dovecot 2.2.13 under Debian 8. I'd like to force an immediate TCP socket disconnect after any imap login attempt that fails. Right now, if invalid credentials are supplied during an imap ...
HippoMan's user avatar
  • 595
5 votes
0 answers
5k views

Sudo won't accept correct password

I'm having a weird problem; sudo isn't accepting my absolutely correct password on my new Kubuntu install. This happens in terminal and in graphical sudo prompts, like if you double click a .deb or ...
Dan Scally's user avatar
1 vote
1 answer
2k views

Why must I provide authentication to mount SATA HDDs? Why are they in read-only mode?

I am running Fedora 36, and have two or three HDDs connected via SATA (including the drive that Fedora on). When I attempt to access the drives in the file manager for the first time since power-on, ...
TheLabCat's user avatar
  • 113
1 vote
1 answer
7k views

X11VNC - connection failed due to incorrect password even though password correct

Running Xubuntu 20.04 as VM on top of Ubuntu Server 20.04 with bridged interface. I am able to connect to the VM via SSH (also using Putty on Windows 10 machine that will access the VM). Using ...
rbaleksandar's user avatar
4 votes
0 answers
609 views

Making multiple PAM modules work together with success as soon as any of them return successfully

I basically want to unlock any sudo authentication with any of these criteria met (whatever completes first successfully): a usb as a security key matched (custom script). fingerprint matched. ...
Animesh Sahu's user avatar

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