Gotenberg is a document transformation and conversion library used by developers and companies to automate the conversion of office files to PDF. It is often integrated into larger software solutions requiring document handling capabilities. Gotenberg is popular due to its open-source nature, flexibility, and ease of integration. The application is particularly favored in environments where document management and processing efficiency are critical. Businesses across various industries like legal, finance, and education employ Gotenberg for its robust document conversion features.
Server-Side Request Forgery (SSRF) is a critical vulnerability that allows an attacker to make requests from the server to internal or arbitrary external services. By exploiting SSRF, attackers can access internal systems, read sensitive files or data, and potentially perform numerous malicious activities under the guise of the vulnerable server. The Gotenberg vulnerability allows unauthorized access to internal resources via document file processing. This vulnerability can also be exploited to initiate outbound requests to attacker-controlled endpoints.
The SSRF vulnerability in Gotenberg exists at the /forms/libreoffice/convert endpoint. This endpoint allows users to upload DOCX files for conversion by LibreOffice. By embedding external references in these DOCX files, attackers can direct LibreOffice to fetch resources using file:// or http/https schemes. Therefore, local files or external resources can be accessed or leaked when converted to PDFs. The flaw allows attackers to manipulate these processes to fetch maliciously controlled URLs or access forbidden internal files.
When exploited, the SSRF vulnerability in Gotenberg can lead to severe consequences, including unauthorized disclosure of sensitive information. Attackers can gain insight into internal network architecture or read local files that the server can render. Moreover, SSRF could be a stepping stone to further attacks, using information gleaned from internal systems to compromise other services. This could eventually allow complete control over affected systems depending on the severity of the accessed data.
REFERENCES
- Update Gotenberg to version 8.34.0 or later.
- Implement strict input validation to disallow external resource referencing.
- Conduct regular security assessments to identify potential vulnerabilities.
- Restrict server's outbound network connections to essential services only.
- Utilize firewalls to monitor and control requests made to and from the application server.
Get AI-powered remediation steps tailored to your asset.
Try AI Solutions →