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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.

0
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1answer
16 views

lynx proxy authorization

A number of scripts on my system are relying on lynx which in turn can't pass through my proxy. More specifically, lynx successfully picks up the global proxy settings except the user id and password ...
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0answers
13 views

Authentication and management of wifi users using Linux

I need a way of controlling a wifi connection (basically a hotspot) by permiting a user to log in using his email and his table number through a website (think like a restaurant with a eletronic ...
0
votes
1answer
26 views

Basic Authentication of Squid - /usr/lib64/squid/basic_ncsa_auth file not found

I have centos 7.6 & installed squid 4.5 on it. sudo yum -y install squid I followed this link for Basic Authentication. Without authentication squid works fine. Here is squid.conf after ...
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0answers
12 views

PAM successful authentication limits

I have a question regarding PAM and the possibility that it throttles too many 'auth' attempts if they happen in a short time. I have posted my question on the PAM mailing list, but to no avail. I ...
0
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1answer
30 views

Passwordless(MFA) login Linux

On windows there is Windows Hallo with support for bio-metrics/pin/yubikey/smartphone app. Even if it's not a 1:1 alternative Im looking for something similar. Is there any way to set up multi-factor ...
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0answers
21 views

sshd_config AllowUsers not working for Active Directory users Centos & [duplicate]

I am able to authenticate with my CentOS 7 server using Active Directory account in the format of domain/user or user@local.domain. However, when I edit the sshd_config file and try to explicitly ...
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0answers
38 views

login not working from new tty but with su <username> works

I'm installing LDAP auth on CentOs7 (command-line way). I'm facing a strange behaviour: [root@client]# su ldapuser01 (run as root) works and let me connect as ldap user (without prompting for a ...
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0answers
28 views

NTLMv2 authentication with Centos7

I have a Centos7 VPS with Apache 2.4 and i use it only as a web server. I use web services of a company that needs NTLMv2 authentication. I use CURL to get the data for the web services for other ...
0
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2answers
66 views

auth not working in apache

I was trying to enable authentication in apache . I tried the following configuration items. <Directory "/var/www/html/balancer-manager"> Order deny,allow AuthName "Restricted area for ...
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3answers
52 views

PAM doesn't block my account after 5 failed logins

I would like to block account after 5 failed password on login screen. I follow this article but it doesn't takes effect. I don't know why. This is the content of my /etc/pam.d/system-auth file : #%...
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1answer
27 views

Secondary password file creation and reset

Is there any way to reset all passwords previously created when the secondary password file is enabled for the first time to ensure higher-level protection ?.
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1answer
75 views

PAM conf files are insecure! [closed]

PAM configuration files located in /etc/pam.d/ are vulnerable to physical attack. That is they can be modified from an external system (bootable USB or take drive to another machine) Other than ...
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0answers
421 views

Ubuntu 18.04 netplan configuration for WPA-EAP

Background I'm using Ubuntu 18.04 server (on a laptop, for development) and am trying to get my wifi configured to work with an WPA-EAP network. To enable Wifi I followed the guide Wifi on Ubuntu 18 ...
1
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1answer
36 views

Possible to get sshd (openssh) to log the public key of failed key based login attempts?

As I understand sshd (openssh in my case) typically does/may log the fingerprint/hash of the public key of incoming connections which are attempting to authenticate via key. What I'm looking for is ...
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0answers
78 views

How to generate keytab for headless AD user

I was provided a headless Active Directory user account with a randomly generated password we need to use to access some network resources. Since this headless account will need to be run from an ...
1
vote
1answer
424 views

ldap users unable to ssh to the server

I have configured ldap local server running centos 7, using this article: https://www.itzgeek.com/how-tos/linux/centos-how-tos/step-step-openldap-server-configuration-centos-7-rhel-7.html. Now my ...
2
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0answers
494 views

Add LDAP server certificate to trusted list and enable certificate verification

I am trying to use a secure LDAP connection via TLS ldaps://<server_name>:<port> for various applications (e.g. Gitlab). However, the connection raises certificate errors which is due to ...
1
vote
1answer
283 views

SSH fails with error “Permission denied (Password)”

I am trying to SSH into a PC (lets call it B) with Ubuntu Server 18.04 from a Raspberry Pi (lets call it A) with Raspbian Stretch Lite. Both are on my local network. PublicKeyAuth is disabled and ...
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0answers
86 views

For rotating logs- Cronjob issue

Invoking logrotate every 15 mins. logrotate will rotate only after size threshold crosses 1M Working machine [root@machine1 output]# ls -l --block-size=1K total 296 -rw------- 1 root root 55 Oct ...
6
votes
2answers
220 views

setting sudo password different from login password

I am attempting to use PAM to use a different password for sudo than I do for logging in. I worked off of this post originally Set sudo password differently from login one Unfortunately, every time ...
3
votes
0answers
26 views

Authentication of users via HTTPd with certificates and two CAs

I would like to implement an internal site for our company, with certificate authentication used wherever possible. I have run into (and tried) various examples where one creates their own self-signed ...
2
votes
2answers
57 views

Downloading using curl, username and password required (cookie, phpsessid, etc…) [closed]

I am trying to download files using curl and chrome extension called CurlWget. When I click on a file to download it, I get this message: wget --header="Host: www.dummy-website.com" \ --header="User-...
1
vote
1answer
60 views

Arch linux set up wifi issue

I've just finished setting up arch linux and am trying to configure wifi (wired internet works ok I checked). As for wireless I have this issue: I try to connect to wireless router with iw dev ...
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0answers
11 views

How to create a dummy printer with AuthInfoRequired option

How can I create a dummy printer for CUPS that has realistic support for the AuthInfoRequired option? Ideally this would work even when having the printer on localhost. I was thinking about CUPS-PDF, ...
1
vote
1answer
197 views

Authenticate Linux<->LDAP Protocol<->AD(active directory): Fail to logon with password

Dears, I spent much time on this and even successfully verified (Auth)Linux-LDAP-openLDAP ok. But get blocked with AD.I can now switch to user from root account but can not log on with password(...
0
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1answer
21 views

MySQL - OS tied users

So, I'm trying to find this option and I can't find it in the docs. I need to know if there is a way in MySQL in which every user on the OS is also a User on the dB. Just to clarify, when using ...
1
vote
1answer
422 views

Unable to log in to tty1 password incorrect? [closed]

In the console tty1 I can't access with my login and password. It states that my password is incorrect however my password is correct?
1
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2answers
50 views

Bypass Apache Authentication for specific IP

We're using Apache as a reverse proxy, so some of our internal development/testing servers are accessible on the open Internet for UAT/CAT purposes. We have basic authentication setup through LDAP ...
0
votes
2answers
35 views

How do I activate time based admin login to a Linux system using windows active directory?

I have set up a solution where the login to our linux systems is regulated by microsoft active Directory and group memberships. Now i want the access time based so that the ad user will be kicked out ...
1
vote
0answers
267 views

pam_sss access denied with kerberos authentication ok [closed]

I'm trying to use sssd with kerberos authentication and ldap on Ubuntu 18.04 (server and client machine). On Ubuntu client side I installed sssd sssd-tools packages. But when I want to log in to alice,...
8
votes
4answers
3k views

How does Linux identify users?

I mean, if two users have the same name, how does the system know that they're actually different users when it enforces file permissions? This doubt came to my mind while I was considering to rename ...
3
votes
1answer
621 views

Using pam_exec.so to run a script as root when a user logs in (while extracting user information)?

Question How can I run a script as root when a user logs in with pam_exec.so (or otherwise)? The script requires information about the user to function. Problem and Environment I would like to run ...
1
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1answer
729 views

How do I correctly configure exim4 on Debian so I can use `sendmail -t` to send mail via my office365 account?

I'm using Debian stretch (9.4). I have an office365 account. Using Evolution, I can successfully download mail via POP3, and also send mail using the Evolution "Sending E-mail" preferences: Server: ...
0
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1answer
101 views

Regarding PAM via ldap

I have a question for the authentication between Linux and Windows. When I get an authentication from the OS system such as Linux, then I can use PAM by configuration of "/pam.d". However, it's the ...
-1
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0answers
30 views

Authentication password changed?

When I installed linux mint 18.3, I set a password. Then I changed the admin of the device but the old password isn't accepted. Any thoughts?
1
vote
1answer
757 views

How to make changes to pam config such that further execution of authconfig will not overwrite them?

I'm configuring a CentOS7 host (through ansible) running authconfig. Now I need to add/configure pam_exec module to the setup but it seems it is not supported by authconfig (cf. man authconfig and /...
1
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2answers
2k views

ssh through authentication requiring proxy

At work we have of course a company's-proxy. I need to ssh to some machines out of the company's network. The proxy though requires authentication. lets assume we have the following variables: ...
0
votes
1answer
1k views

LDAP server setup with GUI on CentOS7

I have, in the past, set up an LDAP server using OpenSuSE (13.2), which worked well since there was a YaST module which allowed a GUI set-up. Now I have the problem that I must set up an OpenLDAP ...
0
votes
1answer
195 views

White List and Black List for SSH

How to create a (username/password or certificate) white/black list for ssh? For example of blacklist, I can use any username/password combination to access the server, except the ones on the ...
1
vote
2answers
946 views

How to verify that ssh certificate was signed by specified ssh CA private key?

I am trying to harden my ssh setup using this material. It works fine, but I've got a question which I'm struggling to find the answer to. Does anyone know if there is a way to check the ssh host/...
0
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0answers
31 views

How to use 2FA with cert based SSH auth?

I used this guide to enable Google TOTP auth on Ubuntu 16.04. SSH only allows cert based auth (PasswordAuthentication no) I set ChallengeResponseAuthentication yes and restarted the SSH service. I ...
2
votes
1answer
103 views

How to enable usage of SSH keys pair without exposing it

We have a topsecret@remote.org SSH account that can be accessed with SSH key pair ts_key.pub/ts_key.priv from our gateway server (gateway.org). We have many sysadmins that need to access that account. ...
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votes
2answers
57 views

How to copy public key to the server that doesn't allow password?

I configured my server to not allow password authentication. Now I have a new machine in a remote location, how is it possible for me to generate an ssh key and do an ssh-copy-id to the server if the ...
1
vote
1answer
46 views

Can two local users on two separate machines use SSH keys to authenticate without passwords?

I have two local users (whose homes directories are listed under /localhome/user) on two separate VMs on the same network. They share the same uid (set in /etc/passwd) and the same username (<user&...
0
votes
1answer
151 views

Why does the pam_unix module documentation list PAM_IGNORE as its only return value?

From http://www.linux-pam.org/Linux-PAM-html/sag-pam_unix.html: 6.37.4. RETURN VALUES PAM_IGNORE Ignore this module. Obviously the module must return success or failure for password ...
0
votes
1answer
235 views

LDAP authentication and default groups

I have multiple RHEL 7.4 servers with LDAP authentication via sssd. Conveniently, my university's LDAP environment has a UIDNumber attribute that is unique for every person. My sssd.conf is at the end ...
1
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0answers
339 views

Access SMB shares using stored credentials

Assuming I have a network of a few Windows computers, and I set up the same user with the same password on all computers, this user will be able to access any shares on any of the computers - without ...
1
vote
1answer
70 views

How to allow any user to log as a non loggable user?

I'm trying to implement the following functionality on Redhat: I have a user "John" that can't be used to login directly via GDM or console or SSH. I want to allow any user that are logged onto the ...
0
votes
1answer
173 views

OpenBSD LDAP authentication - ypldap high CPU usage

I have an OpenBSD server with login_ldap, ypldap, ypbind and portmapper is configured according to these guides that I managed to find courtesy of Google. http://obfuscurity.com/2009/08/OpenBSD-as-an-...
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0answers
155 views

OpenBSD - login_ldap - ypldap - sudo.ldap and handling of remote and local users

I have an OpenBSD server with login_ldap, ypldap, ypbind and portmapper is configured according to these guides that I managed to find courtesy of Google. http://obfuscurity.com/2009/08/OpenBSD-as-an-...