Name: Freemarker Server Side Template Injection (SSTI) Scanner

Freemarker is a popular templating engine used for Java applications, widely utilized by developers for dynamic web content generation. It is integrated into various web applications to create user interfaces by combining data models with templates. Its primary use is to facilitate seamless data presentation and user interaction on web pages. The vulnerability scanner checks software applications employing Freemarker templates to identify potential injection weaknesses. Development teams value Freemarker for its flexibility and capability to enhance user experiences through dynamic content. However, securing Freemarker configurations is essential to prevent exploitation by malicious actors.

Server Side Template Injection (SSTI) is a critical vulnerability detected in web applications using templating engines like Freemarker. It occurs when user inputs are unsafely concatenated or interpolated within templates, allowing attackers to inject arbitrary code. Such vulnerabilities enable malicious payloads to be executed on the server, potentially compromising security. This scanner identifies conditions indicative of SSTI by testing for unsafe input handling. Identifying SSTI is crucial as it could lead to unauthorized access or data breaches. This vulnerability can be exploited by attackers to execute arbitrary server code, making detection and remediation vital for maintaining application security.

The identified SSTI vulnerability in Freemarker arises from insecure handling of input data in templates. Specifically, the vulnerability is confirmed when user input is directly processed by Freemarker without proper validation or sanitation. Payloads injected into the application exploit this to execute server-side commands via the vulnerable template. This scanner utilizes DNS-based payload injections to test server response and confirms vulnerability by receiving DNS requests triggered by command execution. Key vulnerable endpoints include those accepting or processing user input in conjunction with Freemarker templates. The accurate detection of this injection signifies potential exploitation risks that need addressing.

If exploited, the SSTI vulnerability can lead to severe impacts such as unauthorized remote code execution on the server. Attackers may leverage this to gain extended access to sensitive data and escalate privileges, leading to data breaches. Compromise of application integrity is possible, allowing attackers to deploy harmful software or disrupt service operations. The exploitation could result in significant downtime, service disruption, and potential monetary losses. Furthermore, the exploitation could harm brand reputation due to perceived security weaknesses.

REFERENCES

• https://mvnrepository.com/artifact/org.freemarker/freemarker
• https://medium.com/@0xAwali/template-engines-injection-101-4f2fe59e5756
• https://github.com/swisskyrepo/PayloadsAllTheThings/blob/master/Server%20Side%20Template%20Injection/Java.md#freemarker---code-execution