Blind SQLi

Blind SQL Injection

Blind SQL injection (Blind SQLi) is a type of SQL injection attack where the attacker can exploit the database, but the application does not display the output. Instead, the attacker must "infer" data by sending payloads and observing the application's behavior or responses.

A simple example:

  • A vulnearble webapp uses an API for its search to return the number of results found.

  • A user searches for a product, and the application returns with "X products found" without displaying product details.

  • The application uses the SQL query SELECT COUNT(*) FROM products WHERE product_name LIKE '%{searchTerm}%'.

  • An attacker could exploit this by injecting SQL conditions into the {searchTerm}.

  • For exmaple, searching for laptop' AND 1=1-- - returns "1 product found" and searching for laptop' AND 1=2-- - returns "0 products found", this behavior can be an indicator of a potential Blind SQLi vulnerability.

Blind SQLi is more time-consuming than regular SQLi but is just as dangerous. It can lead to:

  • Sensitive data exposure

  • Data manipulation

  • Authentication bypass

  • Potential discovery of hidden data

Other learning resources:

  • OWASP:

  • SQLmap's guide on Blind SQLi:

  • PenTestMonkey's Cheat Sheet:



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