Web Security Attacks
Common Web Application Vulnerabilities
Web applications face numerous security threats. Understanding these attack vectors is crucial for building secure systems and protecting against malicious activities.
SQL Injection is the process of adding SQL code to queries to interfere with the SQL queries for an application's database. An attacker using SQLi can view unauthorized data, cause irreparable damage to servers, or even launch Denial-of-Service attacks.
How SQL Injection Works:
- Attackers use the SQL comment character (') to manipulate queries
- Most commonly exploited in WHERE clauses of SELECT queries
- Can lead to data theft, data destruction, or system compromise
Command Execution attacks involve crafting HTTP requests to execute system commands on the target server.
Command Execution Details:
- Vulnerability: Using shell commands like nslookup with user input
- Exploitation: Adding operators like && to execute additional commands
- Prevention: Scrub input for malicious characters (;, &, `, |) or avoid shell commands entirely
ClickJacking tricks website users into clicking malicious links that appear to be something else.
ClickJacking Mechanics:
- Attackers create malicious sites using iframes of legitimate sites
- Transparent malicious links are placed over legitimate content
- Prevention: Use Content-Security-Policy HTTP headers to prevent iframe embedding
File Upload Vulnerabilities occur when applications allow users to upload files containing malicious code that can then be executed.
File Upload Attack Process:
- Attackers upload malicious scripts (e.g., PHP files)
- These files are then executed on the server
- Prevention: Store uploaded files on separate servers or use cloud-based storage systems