CVE-2023-29827 Scanner

EJS, a popular JavaScript library used for creating HTML templates with embedded JavaScript, is widely utilized in web development projects. Known for its simplicity and efficiency, it allows users to define HTML templates and pass dynamic data to them, which in turn gets rendered into web pages. Developers across industries leverage EJS for creating dynamic web applications quickly, particularly beneficial in projects requiring server-side rendering. The library's seamless integration with Node.js enhances its utility, promoting ease of use in full-stack development environments. With version management and community support, EJS continues to play a vital role in web application development, addressing diverse requirements in real-time applications. Its flexibility in rendering pages dynamically makes it a preferred choice for many developers looking for a straightforward templating engine.

Server Side Template Injection (SSTI) is a critical vulnerability that poses a significant risk if not properly handled. This type of injection allows attackers to input or edit template syntax, resulting in arbitrary code execution on the server. When the input is not properly sanitized, malicious actors can manipulate template data to execute unintended commands. SSTI can lead to severe implications including data leakage, unauthorized access, and system compromise. It often exploits dynamic page renderings, where user inputs are directly embedded into server-side templates. Recognizing and mitigating SSTI is crucial as it involves the main operating environment, potentially affecting the confidentiality, integrity, and availability of the affected application. Effective prevention strategies include input validation and output encoding to prevent malicious payload execution.

The vulnerability in EJS 3.1.6 arises from its handling of the closeDelimiter configuration setting. In scenarios where the EJS file is controllable, this setting can be misused, enabling template injection attacks. A critical aspect of this vulnerability is the interaction with the 'page' endpoint, where unsanitized input might be processed. The vulnerability is further highlighted when malicious template syntaxes are fed into this parameter, leading to arbitrary code execution on the server running the applications. Attack scenarios often involve manipulating URL parameters to execute remote commands or scripts under the file execution context of EJS. The criticality of this vulnerability lies in the improperly restricted configurations that might expose systems to harmful activities. This necessitates vigilance in how configurations and templates are managed within applications leveraging EJS.

Exploitation of this vulnerability can lead to severe repercussions including unauthorized command execution with potential for server takeover. Malicious attackers can exploit this weakness to execute arbitrary code, which may escalate to a full-compromise of the application or server. Such exploits can result in data breaches, system downtimes, and loss of sensitive information, affecting both the integrity and availability of the application. The risk perspective includes unauthorized data access or modification, system performance degradation, and exploitation to launch further attacks within the networked environment. Addressing this issue is paramount to maintaining the security posture of applications utilizing EJS and preventing potential exploitation by cybercriminals.

REFERENCES

• https://github.com/mde/ejs/issues/720
• https://github.com/mde/ejs/blob/main/SECURITY.md#out-of-scope-vulnerabilities
• https://nvd.nist.gov/vuln/detail/CVE-2023-29827