CHAP Password decrypt - Freeradius

Question

I'm using Freeradius to authenticate user from my server using php code

update control {
    Reply-Message := `/usr/bin/php -f /etc/raddb/auth.php '%{User-Name}' '%{CHAP-Password}' '%{CHAP-Challenge}' auth`
}

it return CHAP-Password = 0xa2a421bf267fbffabe5696cf1c6d54f479

and the CHAP-password is Hashing, but i don't have clear text password in database, the password is hashed .

It is working fine with PAP Protocol, but i need to use CHAP for other server configuration

So my question: is there anyway to decrypt the CHAP-Password , or if this is not possible to tell CHAP not to hashing the password in configuration

Answer 1

After searching for many and many hours I finally make chap authenticate with my database:

First: I'm working on freeradius 3, because there are many changes form radius 2 and radius 3

Second: Database Configuration

I'm using mysql with 2 Databases like this:

1. members

   • users
     • id
     • username
     • password
     • .......
     • .......
   • ........

2. radius

   • radcheck
     • id
     • username
     • attribute
     • op
     • value
   • radpostauth
   • ......

You need to configure sql file in this root

sudo nano mods-available/sql

And change this values

driver = "rlm_sql_mysql"
dialect = "mysql"
server = "localhost"
login = "your_database_username"
password = "your_database_password"

Then save and restart the radius by:

sudo service radiusd restart

If radius restart without error, so the configuration is correct

After restarting radius you need to copy this file to mods-enabled

so radius run this configuration, because all files in mods-enabled is what radius running it

sudo cp mods-available/sql mods-enabled/sql

To check if everything running OK

sudo radiusd -XC

This command run debug on radius, and return errors .

if the end of this debug is

Configuration appears to be OK

so everything is fine until now

Third: Database Connection and Authenticate

Now we need to authenticate the username via CHAP , so we need to write query to select the username from user table

This query will be in this file queries.conf in this root

sudo nano mods-config/sql/main/mysql/queries.conf

And change the authorize_check_query to

authorize_check_query = "\
    SELECT members.user.id as id, \
    members.user.username as username, \
    'Cleartext-Password' as attribute, \
    members.user.password as value, \
    ':=' as op \
FROM members.user \
WHERE members.user.username = '%{SQL-User-Name}' \
ORDER BY members.user.id"

FYI , the password must be in plain text, because as you see the attribute is Cleartext-Password

Now let's add in table user row with username = "ahmed" and password = "test"

and try to test authentication

radtest -t chap ahmed test localhost 1812 testing123 

if you receive

Received Access-Accept Id 105 from 127.0.0.1:1812 to 127.0.0.1:38259 length 20

So you are Done,

also i want to thanks @MatthewNewton for his answer and comments on my question :D