CVE-2024-26263: Ebmtech Risweb Auth Bypass Vulnerability

CVE-2024-26263 Overview

CVE-2024-26263 affects EBM Technologies RISWEB, a Radiology Information System web application. The vulnerability stems from missing authentication controls on specific URL paths within the application [CWE-306]. Unauthenticated remote attackers can browse restricted pages and query sensitive data without supplying credentials.

The flaw is exploitable over the network with low attack complexity and requires no user interaction. Affected deployments expose confidential medical and operational data to anyone who can reach the web interface. The advisory was published by the Taiwan Computer Emergency Response Team (TWCERT).

Critical Impact
Remote attackers can access sensitive radiology data through unauthenticated requests to specific URL paths in RISWEB.

Affected Products

EBM Technologies RISWEB (all versions prior to the vendor's fixed release)
Deployments exposing the RISWEB web interface to untrusted networks
Radiology Information System instances using vulnerable RISWEB URL handlers

Discovery Timeline

2024-02-15 - CVE-2024-26263 published to the National Vulnerability Database
2025-01-23 - Last updated in NVD database

Technical Details for CVE-2024-26263

Vulnerability Analysis

The vulnerability is a Missing Authentication for Critical Function weakness [CWE-306] in EBM Technologies RISWEB. Specific URL paths within the application do not enforce session or permission checks before returning content. Attackers who know or can enumerate the affected paths receive responses that should be restricted to authenticated users.

Because RISWEB serves Radiology Information System data, the exposed pages can include patient records, imaging metadata, and operational queries. The confidentiality impact is rated High in the CVSS vector, while integrity and availability are not affected. Exploitation does not require privileges or user interaction.

Root Cause

The root cause is an authorization gap in the web application's request handling layer. The application enforces login on standard entry points but omits permission checks for one or more secondary URL handlers. This inconsistency allows unauthenticated HTTP requests to retrieve protected pages and query endpoints directly.

Attack Vector

An attacker sends crafted HTTP requests to the vulnerable URL paths on an exposed RISWEB instance. The server processes the request without validating an authentication token or session cookie and returns sensitive data in the response. No malware, credentials, or social engineering are required.

No public proof-of-concept code is available for CVE-2024-26263. Technical details are documented in the TWCA Security Advisory.

Detection Methods for CVE-2024-26263

Indicators of Compromise

HTTP GET requests to RISWEB application paths that return 200 OK responses without a preceding authentication redirect or session cookie
Access log entries showing repeated requests to non-public RISWEB URLs from external or unexpected source IP addresses
Outbound data transfers from RISWEB hosts that correlate with unauthenticated request bursts

Detection Strategies

Review web server access logs for requests to RISWEB endpoints lacking valid session identifiers in cookies or headers
Compare traffic patterns against an inventory of authenticated user sessions to identify anonymous data retrieval
Deploy web application firewall rules that flag direct access to administrative or query URL paths without prior login activity

Monitoring Recommendations

Continuously monitor RISWEB application logs for unusual response sizes returned to unauthenticated sessions
Alert on access from IP ranges outside the expected clinical network perimeter
Track HTTP 200 responses to URL paths that should normally require authentication and trigger investigation on anomalies

How to Mitigate CVE-2024-26263

Immediate Actions Required

Restrict network access to the RISWEB web interface using firewall rules or VPN-only access until a patch is applied
Contact EBM Technologies to obtain the fixed release and apply it across all RISWEB deployments
Audit web server access logs for evidence of unauthenticated access to sensitive URL paths since the vulnerability was disclosed

Patch Information

EBM Technologies has addressed the issue per the coordinated disclosure published by TWCERT. Administrators should reference the TWCA Security Advisory and contact the vendor for the patched version and upgrade instructions specific to their deployment.

Workarounds

Place RISWEB behind a reverse proxy that enforces authentication before requests reach the application
Use network segmentation to limit RISWEB exposure to authorized clinical workstations only
Apply web application firewall rules that block direct requests to known unauthenticated URL paths identified in the advisory

bash

# Example reverse proxy authentication enforcement (nginx)
location / {
    auth_request /auth;
    proxy_pass http://risweb_backend;
}

location = /auth {
    internal;
    proxy_pass http://auth_service/validate;
    proxy_pass_request_body off;
    proxy_set_header Content-Length "";
}