Data Breaches are common, and their cause is often as simple as the use of weak passwords.
SQL Server has an internal system function, PWDCOMPARE(), that can be used to find SQL logins with a weak password. A list of very common weak passwords can be found here as well as many other places.
IF OBJECT_ID('tempdb..#CommonPasswords') IS NOT NULL DROP TABLE #CommonPasswords; CREATE TABLE #CommonPasswords(Password varchar(30) COLLATE Latin1_General_CS_AS not null primary key); INSERT INTO #CommonPasswords(Password) VALUES (''), ('123'), ('1234'), ('12345'), ('123456'), ('1234567'), ('12345678'), ('123456789'), ('1234567890'), ('987654321'), ('123qwe'), ('mynoob'), ('18atcskd2w'), ('55555'), ('555555'), ('3rjs1la7qe'), ('google'), ('zxcvbnm'), ('000000'), ('1q2w3e'), ('1q2w3e4r5t'), ('1q2w3e4r'), ('qwerty'), ('qwerty123'), ('password'), ('p@ssword'), ('p@ssw0rd'), ('password1'), ('p@ssword1'), ('password123'), ('passw0rd'), ('111111'), ('1111111'), ('abc123'), ('666666'), ('7777777'), ('654321'), ('123123'), ('123321'), ('iloveyou'), ('admin'), ('nimda'), ('welcome'), ('welcome!'), ('!@#$%^&*'), ('aa123456'), ('lovely'), ('sunshine'), ('shadow'), ('princess' ), ('solo'), ('football'), ('monkey'), ('Monkey'), ('charlie'), ('donald'), ('Donald'), ('dragon'), ('Dragon'), ('trustno1'), ('letmein'), ('whatever'), ('hello'), ('freedom'), ('master'), ('starwars'), ('qwertyuiop'), ('Qwertyuiop'), ('qazwsx'), ('corona'), ('woke'), ('batman'), ('superman'), ('login'); SELECT name, create_date, is_disabled FROM sys.sql_logins sl (nolock) cross apply #CommonPasswords cp WHERE PWDCOMPARE(cp.Password, sl.password_hash) = 1 UNION ALL SELECT name, create_date, is_disabled FROM sys.sql_logins sl (nolock) WHERE PWDCOMPARE(sl.name, sl.password_hash) = 1; -- password same as username
Troy Hunt has collected the passwords from several major data breaches, and he has made the passwords searchable.