Preventing SQL Injection Attacks

A structured query language (SQL) injection attack is a malicious web attack technique that makes it possible to bypass web page and web application security measures by executing malevolent SQL statements. Using this attack technique, hackers can retrieve, add, modify and delete the contents of an SQL database.

SQL is the command-and-control language for relational database management systems (RDBMS) like Microsoft SQL Server, MySQL, Oracle Database, and IBM Db2. A SQL injection attack can affect any website or web application that uses an SQL database system. Given the ubiquity of SQL databases, SQL injections (SQLi) are prevalent on the internet.

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 What damage can an SQL injection attack cause?

Hackers can exploit security flaws to cause extensive enterprise damage. Here is how cybercriminals can use SQL injection attacks:

1. Attackers can use SQL injection attacks to find the login credentials of other users in a database and impersonate them. To put it into perspective, if a hacker gains administrative authority, he can create havoc. These login credentials can be used to attack other websites as well.
2. Hackers can gain access to all the data in a database server. This includes credit and debit card details, social security numbers, etc.
3. In the case of financial websites and applications, hackers can use an SQL injection attack to transfer money to their account, void transactions, and alter balances.
4. Hackers can delete records from a database. While DBMS software offers recovery and backup, backups may not cover recent data. Hackers can corrupt the database and make the website unusable.
5. A complex SQL injection attack can enable attackers to access an operating system using the database server.
6. Attackers can inject further malicious code that will only be executed when users visit the website.

SQL injection attacks are the biggest threat to application security, as nearly two-thirds of all the attacks on software applications between 2017 and 2019 were SQLi. Despite technological security advancements since SQL injections were first discovered in 1998, they are still a major cause of concern.

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What can be done to combat SQL injections?

Here is what you can do to protect your organization from SQL injection attacks:

• Use an SQLi detection tool: An SQLi detection tool automatically identifies potential security vulnerabilities that can be exploited by wrong-doers. Some of the most popular SQL injection detection tools include SQLMap, jSQL, BBQSQL, Blind-SQL-Bitshifting, Blisqy, Damn Small SQLi Scanner (DSSS) and explo.
• Input validation/query redesign: You should identify essential SQL statements and set up a whitelist, not a blacklist (smart attackers may find a way to circumvent a blacklist), for all valid SQL statements. You should also configure input fields by context. For example, input fields for phone numbers can be filtered to only allow required special characters, like ‘+’ and ‘-‘. The same applies to email addresses, credit and debit cards, social security numbers, etc.
• Data sanitization: You should sanitize data by limiting special characters. SQLi attackers can take advantage of security shortcomings to access a database by using unique character sequences. It is essential that you sanitize data to not allow string concatenation. If you are using MySQL database management software, for example, you can configure user inputs to mysql_real_escape_string(). This can go a long way in ensuring that special characters like a single quote (‘) are not passed to a SQL query as an instruction.
• The use of prepared statements with parameterized queries is critical: Unfortunately, input validation and data sanitization alone is not enough to prevent SQLi. Enterprises must also use prepared statements with parameterized queries (variable binding). This will help distinguish between input data and a potential command. You should use stored procedures in the database as well.
• Actively apply patches and updates: Security shortcomings can be identified by the public and these vulnerabilities are exploitable using SQLi. It is of the essence that organizations consistently manage patches and updates. This means keeping DBMS software, frameworks, web server software, libraries and plug-ins up to date. We recommend using a patch management solution like SolarWinds Patch Manager, Flexera Corporate Software Inspector, IBM BigFix, Ivanti Patch or Red Hat Satellite.
• Use a web application firewall (WAF): A software or appliance-based WAF is handy when it comes to filtering potentially dangerous web requests. A WAF’s SQL injection defense can squash most attempts to infiltrate a database.

SQL injection attacks pose a great threat to the security of enterprise data. Hackers can access, modify, add and delete the contents of a SQL database. To mitigate the threat of SQLi, it is important that you craft your database security system to treat all user data as potentially malicious.

Apply patches and updates at the earliest to prevent hackers from taking advantage of SQL vulnerabilities. Keep in mind all the tips mentioned in this guide and explore advanced protection options to maximize enterprise security.

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