Basics of Server Side Template Injection
- 1. Basics of ServerSide Template Injection By Shrutirupa(@freak_crypt)
- 2. What are TemplateEngines?
- 3. Template Engines are: 1.Widely used by web applications for dynamically generating data. 2. These data are generated through web pages or emails.
- 4. What is ServerSide Template Injection?? 1. We are able to inject some malicious piece of code through the improper/unsafe embedded input into the templates used 2. This may result into the execution of commands at the server side
- 5. What is thefirst step towards detecting an SSTI?
- 6. 1. Unusual behaviour 2.Errors 3. Mathematical expressions getting executed
- 7. Ways to detect: 1.{{4*6}} 2. {4*6} 3. ${4*6} 4. ${{7*7}} 5. <%= 7 * 7 %> https://github.com/swisskyrepo/PayloadsAllTheThings/tree/master/Server%20Side%20Template%20I njection
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- 9. Figuring out thetemplates used at the backend!!!
- 11. Based on thetemplate used, injecting codes accordingly
- 12. An example: Let’s goto: http://challenge01.root-me.org/web-serveur/ch41/
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- 16. Mitigations 1. Executing users’code in a sandboxed environment to lower the risk 2. Sandboxing inside a locked down Docker container 3. Validation of input field is always one way to avoid any malicious user to enter any unethical code
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