Databases, Systems & Networks

In order to log in to a MySQL server, you can run mysql command along with your login credentials and server’s IP address as arguments. For example:

$ mysql -u $MYSQL_ROOT -p $MYSQL_PASS -h 192.168.10.1

However, besides the inconvenience of typing extra arguments, using plain-text login credentials in a command line like above is really not a secure way to access a MySQL server. In a multi-user Linux environment, what you type in command line can easily be revealed to others who happen to run ps on the same host at the same time.

MySQL offers a way for you to log in to MySQL server without password, by using an external MySQL configuration file. In Linux, there are two different kinds of MySQL configuration files: (1) /etc/my.cnf and (2) ~/.my.conf. While any system-wide MySQL configuration is defined in /etc/my.cnf, any user-specific MySQL configuration is stored in ~/.my.cnf. You can leverage ~/.my.cnf, to define your MySQL login credential in the file.

$ vi ~/.my.cnf

[client]
user=alice
password=alice_passwd
host=192.168.10.1

Make sure to have the configuration file readable to you only.

$ chmod 0600 ~/.my.cnf

Once ~/.my.cnf is created, simply typing mysql command will let you log in to 192.168.10.1 as alice, and you no longer need to provide login password separately.

Source: Xmodulo

Que ce soit lors de la première installation ou après la perte du mot de passe principal de MySQL, il est nécessaire de pouvoir modifier le mot de passe administrateur (root) de MySQL.

Pour pouvoir modifier le mot de passe root de MySQL, il faut pouvoir s’y connecter, Or, si vous n’avez pas le mot de passe root actuel, vous vous retrouvez alors dans une situation kafkaïenne. Si vous connaissez le mot de passe actuel de MySQL et que vous souhaitez juste changer le mot de passe root, vous pouvez sauter cette étape ! Lire la suite…

Source: faqforge.com

If you lost your ISPConfig 3 administrator password, you can reset it with the following SQL query.

UPDATE sys_user SET passwort = md5(‘admin’) WHERE username = ‘admin’;

The SQL query sets the password to “admin” for the user “admin”, it has to be executed in the ISPConfig mysql database, e.g. with phpmyadmin. If you dont have phpmyadmin installed, then the query can be executed with the mysql commandline utility as well:

Login to the mysql database.

mysql -u root -p

and enter the password of the mysql root user. To switch to the ISPConfig database, run this command:

use dbispconfig;

Now execute the SQL command:

UPDATE sys_user SET passwort = md5(‘admin’) WHERE username = ‘admin’;

and close the mysql shell:

quit;

Abstract

The OTPW package consists of the one-time-password generator otpw-gen plus two verification routinesotpw_prepare() and otpw_verify() that can easily be added to programs such as login or ftpd on POSIX systems. For platforms that support the Pluggable Authentication Method (PAM) interface, a suitable wrapper is included as well. Login software extended this way will allow reasonably secure user authentication over insecure network lines. The user carries a password list on paper. The scheme is designed to be robust against theft of the paper list and race-for-the-last-letter attacks. Cryptographic hash values of the one-time passwords are stored for verification, either in the user’s home directory or in a dedicated system directory.

Introduction

A well-known classic vulnerability of the Internet application protocol suite is the frequent cleartext transfer of passwords in the telnet, rsh, and ftp protocols. Modern replacements for these protocols such as Tatu Ylönen’sSecure Shell allow comfortable and secure remote sessions and file transfers over network connection that are not trusted to provide confidentiality.

However, traveling computer users often want to connect to their home system via untrusted terminals at conference hotels, other universities, and airports, where trusted encryption software is not available. Even Secure Shell does not protect against keyboard eavesdropping software on the untrusted terminal. A loss of confidentiality is often acceptable in these situations for the session content, but not for reusable login passwords. One-time-password schemes avoid the transmission of authentication secrets that are of any value after they have been used. This provides a reasonable level of protection against the widely encountered password sniffing attacks. The goal of a one-time-password login scheme is merely to provide a significant increase of security over the classic telnet/rlogin login procedure. It does not aim to protect from sophisticated active attacks such as session hijacking, host emulation, man-in-the-middle, etc. against which ssh and SSL based protocols should be used if this level of protection is required.

A widely known one-time-password scheme is S/KEY [Hal94, HM96]. OTPW is not compatible with and is not derived from either S/KEY or OPIE. It is a completely independent and different design, which I believe fulfils my functional and security requirements better.

How it works

One-time password authentication with the OTPW package is accomplished via a file containing hash values of passwords. Depending on the installation option chosen, this can either be a file ~john/.otpw located in the user’s home directory, or it can be a file ~otpw/john in the home directory of a dedicated pseudo user “otpw”. In the latter case, the otpw-gen tool for generating new passwords must be owned by pseudo user “otpw” and have the SETUID bit set. As long as users do not have such a hash file, the one-time-password facility is not active for them.

A user who wants to setup the one-time-password capability just executes the otpw-gen program. The program will ask for a prefix password that the user has to select and memorize and it will then write to standard output a password list such as:

  OTPW list generated 2003-08-31 21:06 on trillium.cl.cam.ac.uk

  000 IZdB bqyH  006 rF62 k6zi  012 JCFe 6at3  018 uaYT azuu  024 Nt7n b=fQ
  001 yCSo /VQs  007 Phvb =6ZW  013 8Pm7 DbYJ  019 OdAk H62c  025 /pOm :ZEA
  002 mESf  nWK  008 J9fH iXrn  014 MAds 6TTS  020 Aj6W 9O4P  026 DhCc yrPY
  003 x4vX HXr2  009 DGPC amts  015 B=xZ waPx  021 MzUP Ahsc  027 UWTe G3Fh
  004 A5z9 japt  010 s6cr xwZ5  016 sCgq Da5Y  022 Q=XK 4I7w  028 xszW Ha9L
  005 YCcA k29/  011 inn6 Rsa/  017 m8za o/HB  023 umS= gYoU  029  HmG Rr6P

              !!! REMEMBER: Enter the PREFIX PASSWORD first !!!

Normally the output of otpw-gen should be sent directly to the printer as in

  otpw-gen | lpr

or should be first formatted with an ASCII to PostScript converter where necessary.

Fetch the printed list immediately from the printer, fold it, and keep it with you. The list shows the machine name and the creation time to allow users to find the latest list for the right machine. It does not show the user’s name, because nobody is supposed to have the list of anyone else, but printer drivers such as a2ps might add it. Only a single list is required for a set of networked machines on which the user has a common home directory.

By default, otpw-gen generates 60 lines of output. Use the command line options -h lines, -w columns, and -s pages to specify the length of the output. No more than 1000 passwords will be generated at a time.

Where one-time-password authentication is used, the password prompt will be followed by a 3-digit password number. Enter first the prefix password that was given to otpw-gen, followed directly (without hitting return between) by the password with the requested number from the printed password list:

  login: kuhn
  Password 019: geHeimOdAkH62c

In this example, geHeim was the prefix password. The spaces in the password list are just there to increase readability and can be dropped.

A clever attacker might observe the password being entered and might try to use the fact that computers can send data much faster than users can finish entering passwords. In the several hundred milliseconds that the user needs to press the return key after the last character, an attacker could on a parallel connection to the same machine send the code of the return key faster than the user.

To prevent such a race-for-the-last-key attack, any login attempt that is taking place concurrently with another attempt will require three one-time passwords to be entered:

  login: kuhn
  Password 022/000/004: geHeimQ=XK4I7wIZdBbqyHA5z9japt

This might look inconvenient at first, but remember that three passwords will only be requested when someone tries to login simultaneously, which in itself should already cause suspicion. The three requested passwords are randomly selected but they will never include the single password that was requested in the first of the concurrent login attempts. Only the first requested single password will be locked, not any of the requested triples. This way, the three-password method ensures that an attacker cannot disable the OTPW mechanism by locking all passwords. The triple challenge ensures that many ten thousand network connections would be necessary to perform a race attack on the same password triple, which is not practical. The OTPW package creates a symbolic link .otpw.lock in the user’s home directory to lock the first requested password while its input is pending. If a system crash created a stale lock, it will be removed after 24 hours.

Lire la suite…

As someone says, security is a not a product, but a process. While SSH protocol itself is cryptographically secure by design, someone can wreak havoc on your SSH service if it is not administered properly, be it weak passwords, compromised keys or outdated SSH client.

As far as SSH authentication is concerned, public key authentication is in general considered more secure than password authentication. However, key authentication is actually not desirable or even less secure if you are logging in from a public or shared computer, where things like stealth keylogger or memory scraper can always a possibility. If you cannot trust the local computer, it is better to use something else. This is when “one-time passwords” come in handy. As the name implies, each one-time password is for single-use only. Such disposable passwords can be safely used in untrusted environments as they cannot be re-used even when they are stolen.

One way to generate disposable passwords is via Google Authenticator. In this tutorial, I am going to demonstrate another way to create one-time passwords for SSH login: OTPW, a one-time password login package. Unlike Google Authenticator, you do not rely on any third party for one-time password generation and verification.

What is OTPW?

OTPW consists of one-time password generator and PAM-integrated verification routines. In OTPW, one-time passwords are generated apriori with the generator, and carried by a user securely (e.g., printed in a paper sheet). Cryptographic hash of the generated passwords are then stored in the SSH server host. When a user logs in with a one-time password, OTPW’s PAM module verifies the password, and invalidates it to prevent re-use.

Step One: Install and Configure OTPW on Linux

Debian, Ubuntu or Linux Mint:

Install OTPW packages with apt–get.

$ sudo apt-get install libpam-otpw otpw-bin

Open a PAM configuration file for SSH (/etc/pam.d/sshd) with a text editor, and comment out the following line (to disable password authentication).

#@include common-auth

and add the following two lines (to enable one-time password authentication):

auth       required     pam_otpw.so
session    optional     pam_otpw.so

Fedora or CentOS/RHEL:

OTPW is not available as a prebuilt package on Red Hat based systems. So let’s install OTPW by building it from the source.

First, install prerequites:

$ sudo yum git gcc pam-devel
$ git clone https://www.cl.cam.ac.uk/~mgk25/git/otpw
$ cd otpw

Open Makefile with a text editor, and edit a line that starts with “PAMLIB=” as follows.

On 64-bit system:

PAMLIB=/usr/lib64/security

On 32-bit system:

PAMLIB=/usr/lib/security

Compile and install it. Note that installation will automatically restart an SSH server. So be ready to be disconnected if you are on an SSH connection.

$ make
$ sudo make install

Now you need to update SELinux policy since /usr/sbin/sshd tries to write to user’s home directory, which is not allowed by default SELinux policy. The following commands will do. If you are not using SELinux, skip this step.

$ sudo grep sshd /var/log/audit/audit.log | audit2allow -M mypol
$ sudo semodule -i mypol.pp

Next, open a PAM configuration file for SSH (/etc/pam.d/sshd) with a text editor, and comment out the following line (to disable password authentication).

#auth       substack     password-auth

and add the following two lines (to enable one-time password authentication):

auth       required     pam_otpw.so
session    optional     pam_otpw.so

Lire la suite…