The main way: password loophole attack, SQL Server extended stored procedure attack, SQL Injection (SQL Injection), steals backup, etc.

主要手法有：口令漏洞攻击、SQL Server扩展存储过程攻击、SQL注入(SQL Injection)、窃取备份等。

youdao

The vast majority of those millions of passwords became public after the breach of RockYou.com, a social networking applications site penetrated by cybercriminals using an SQL-injection.

FORBES: Researcher Creates Clearinghouse Of 14 Million Hacked Passwords

But most of those sites still remain vulnerable to SQL injection--meaning the same group of hackers or a copycat group could use similar techniques to redirect the sites' visitors to another server hosting malicious software, Danchev argues.

FORBES: Magazine Article

Plenty of folks in the cyber security field have debated whether the rise of Anonymous would actually lead to increased spending on services like protection from DDoS attacks, which can temporarily paralyze a website, and SQL injection-type attacks that can raid a database and sometimes purge it of all contents.

FORBES: Anonymous Takes From The Rich, Gives To... The Cyber Security Industry?