https://www.bytebang.at/Blog/Reset+GLPI+passwords+in+the+database
Enter password: ************
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1739
Server version: 5.1.42-community MySQL Community Server (GPL)
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> use glpi;
Database changed
mysql> select id,name,password from glpi_users;
+----+-----------+----------------------------------+
| id | name | password |
+----+-----------+----------------------------------+
| 2 | glpi | c37093b421c8131b8999d75fd73c55fd |
| 3 | post-only | c37093b421c8131b8999d75fd73c55fd |
| 4 | tech | c37093b421c8131b8999d75fd73c55fd |
| 5 | normal | c37093b421c8131b8999d75fd73c55fd |
+----+-----------+----------------------------------+
4 rows in set (0.00 sec)
mysql> update glpi_users set password= MD5('newPassword') where name='glpi';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> select id,name,password from glpi_users;
+----+-----------+----------------------------------+
| id | name | password |
+----+-----------+----------------------------------+
| 2 | glpi | 14a88b9d2f52c55b5fbcf9c5d9c11875 |
| 3 | post-only | c37093b421c8131b8999d75fd73c55fd |
| 4 | tech | c37093b421c8131b8999d75fd73c55fd |
| 5 | normal | c37093b421c8131b8999d75fd73c55fd |
+----+-----------+----------------------------------+
4 rows in set (0.00 sec)
mysql> exit
Bye.