OWASP Server-Side Request Forgery (SSRF) Explained

Understanding Server-Side Request Forgery (SSRF)

• 💡 Server-Side Request Forgery (SSRF) is an attack technique where an unprotected web server is used as a proxy to send commands to other computers.
• 🎯 This attack often exploits trust relationships between publicly accessible web servers and private internal servers.

Origin and Context of OWASP Top 10

• 📌 The OWASP Top 10, a reference document for critical web application security concerns, originated from a 2003 publication by Dave Wickers and Jeff Williams.
• 🚀 Today, OWASP is an international organization dedicated to enabling trusted application and API development, with tens of thousands of members and hundreds of chapters globally.
• 📈 In the OWASP 2021 Top 10 vulnerabilities list, SSRF is ranked at number 10.

How SSRF Attacks Work

• 🔍 Normally, web servers handle requests for local information or acceptable requests for outside sources, like embedding a YouTube video.
• ⚠️ However, attackers can misuse this functionality to access internal servers or data not meant for public view, such as requesting the source code of a secret project.
• 🛠️ To mitigate this, network defenders should implement a zero-trust strategy, limiting internal asset access from web servers to only necessary employees.

Notable SSRF Attacks and Mitigation

• ⚠️ While OWASP states SSRF attacks are rare, recent high-profile victims include SolarWinds and Capital One.
• 💻 A 2019 SSRF attack against Capital One, believed to be facilitated by a misconfigured Web Application Firewall (WAF), allowed an attacker to gain credentials.
• 🏦 These credentials were used to access an Amazon S3 bucket containing sensitive data from 140,000 credit card applications, including names, addresses, phone numbers, and social security numbers.
• ✅ Implementing a Web Application Firewall (WAF) and ensuring proper configuration are key to preventing such attacks.