What are SQL injection attacks and how to protect against them

Cyberattacks are an ongoing and growing threat to companies of all sizes. Among the myriad tactics employed by cybercriminals, SQL injection (SQLi) attacks are one of the most common and potentially devastating. As the world continues to digitise, the value of data has skyrocketed, making it an attractive target for malicious actors. Let’s take a closer look at SQL attacks and explore what SQL injection attacks are plus how to protect against them.

Overview of SQL injection attacks

SQL injection attacks exploit vulnerabilities in web applications that interact with databases, enabling attackers to gain unauthorised access to sensitive information or even compromise entire systems. Such attacks can result in severe consequences, including data breaches, loss of customer trust, operational disruption and financial penalties. With online services becoming the backbone of modern businesses, SQL injection attacks represent a significant risk to firms in every sector.

The basics of SQL injection hacks

SQL injection attacks occur when malicious SQL statements are inserted into a query input field within a web application. If the application fails to sanitise user inputs properly, these malicious commands are executed by the database, leading to unintended and often harmful outcomes.

It’s worth remembering cybercrime has not only grown in scale but also in sophistication, thanks in part to emerging technologies like artificial intelligence (AI), machine learning (ML) and deep learning (DL) – all of which have served to further complicate the task of maintaining cybersecurity.

Famous examples of SQL injection attacks

• 2008: Heartland Payment Systems
  • Hackers exploited SQL vulnerabilities to steal Heartland’s data on 130 million credit cards, costing the company over $100 million in fines and remediation.
• 2012: Yahoo Voices
  • A group known as the D33Ds Company used SQL injection to expose 450,000 Yahoo account credentials, highlighting poor data security practices.
• 2014: Sony Pictures Entertainment
  • An SQL injection attack contributed to one of the most infamous data breaches, exposing sensitive company emails, unreleased films and employee data.
• 2019: British Airways
  • SQL injection vulnerabilities were reportedly part of a larger cyberattack that compromised 500,000 customer records, leading to significant GDPR fines.

How do SQL injection attacks work

SQL injection attacks are alarmingly prevalent due to the widespread use of SQL-based databases in web applications. Here are the key stages of an SQL injection attack:

1. Identifying a vulnerability
   • Attackers scout web applications for input fields that fail to validate user inputs, such as login forms, search bars or comment sections.
2. Crafting malicious input
   • A hacker inserts malicious SQL code into the vulnerable input field. For example, using ' OR '1'='1 could trick the database into granting unauthorised access.
3. Executing the attack
   • The database processes the malicious input as a legitimate query, potentially exposing sensitive data or modifying the database.
4. Escalating access
   • Skilled attackers may chain vulnerabilities together to gain administrator-level privileges, allowing them to take full control of the database.
5. Exfiltrating or damaging data
   • Once access is secured, attackers can extract sensitive information, delete critical data, or inject malware for further exploitation.
6. Covering tracks
   • To evade detection, hackers often delete logs or implement misleading changes to conceal the breach.

Protecting against SQL injection attacks

While no security measure is entirely foolproof, companies can significantly reduce their risk of SQL injection attacks by implementing the following strategies:

• Validate and sanitise inputs
  • Always validate user inputs to ensure they conform to expected formats. Use parameterised queries or prepared statements to neutralise potentially harmful SQL commands.
• Employ input escaping
  • Escaping special characters in user inputs can prevent them from being interpreted as SQL commands, reducing vulnerabilities.
• Use stored procedures
  • Stored procedures execute predefined SQL queries, limiting the opportunity for hackers to inject malicious commands.
• Restrict database permissions
  • Limit access privileges to the minimum necessary for each user. For example, public-facing applications should not have administrative access to the database.
• Implement a web application firewall (WAF)
  • WAFs filter incoming traffic, blocking known attack patterns, including SQL injection attempts.
• Regularly update software
  • Outdated database management systems, plugins or web application frameworks often contain known vulnerabilities. Regular updates ensure patches are applied.
• Monitor database activity
  • Use monitoring tools to detect unusual queries or spikes in activity that may indicate an ongoing attack.
• Conduct regular security audits
  • Frequent security audits and testing, including penetration tests and code reviews, can help identify and address vulnerabilities before attackers exploit them.
• Educate developers and staff
  • Training employees on secure coding practices and common attack methods fosters a culture of cybersecurity awareness.
• Encrypt sensitive data
  • Encrypting critical information, such as passwords or financial records, minimises the impact of a breach.

SQL injection attacks are becoming more common

In today’s digital landscape, company data is an invaluable asset that must be protected at all costs. While no system is entirely impervious to attacks, taking proactive measures can significantly reduce the likelihood of falling victim to an SQL injection.

One of the most critical steps is maintaining regular backups. A three-backup strategy – storing copies onsite, offsite, and in the cloud – ensures that data can be restored swiftly, even after a catastrophic breach. Cloud providers offer robust security features, such as real-time monitoring and automatic patching, making them an excellent option for safeguarding sensitive information.

The consequences of an SQL injection attack extend beyond immediate operational disruptions. Financial losses, reputational damage, and potential legal repercussions – especially under regulations like GDPR – can cripple a business. By prioritising cybersecurity and fostering a proactive security culture, companies can better defend themselves against the ever-evolving threats posed by cybercriminals.