HTTP Client application in ColdFusion allows remote attackers to bypass access restrictions for web pages on other ports by providing the target page to the mainframeset.cfm application, which requests the page from the server, making it look like the request is coming from the local host.
ColdFusion's HTTP client is vulnerable to a server-side request forgery (SSRF) attack, allowing attackers to bypass access controls and potentially access internal resources. This vulnerability enables attackers to make the ColdFusion server act as a proxy, requesting web pages on other ports as if the requests originated from the local host, leading to unauthorized information disclosure and potential system compromise.
Step 1: Target Identification: The attacker identifies a ColdFusion server running a vulnerable version.
Step 2: Payload Crafting: The attacker crafts a malicious URL pointing to the mainframeset.cfm application, including a parameter that specifies the target URL (e.g., a restricted internal page or a page on a different port).
Step 3: Payload Delivery: The attacker sends the crafted URL to the ColdFusion server, typically via a web browser or other HTTP client.
Step 4: Request Execution: The ColdFusion server, upon receiving the request, uses its internal HTTP client to fetch the content from the target URL specified by the attacker.
Step 5: Access Bypass: Because the request originates from the ColdFusion server itself, it bypasses any access restrictions based on client IP or other client-side checks.
Step 6: Information Disclosure: The ColdFusion server then displays the content of the target URL, potentially revealing sensitive information or allowing further exploitation.
The vulnerability stems from a flawed implementation within ColdFusion's mainframeset.cfm application. This application, designed to fetch and display content, fails to properly validate the origin or target of HTTP requests. Specifically, it accepts a user-controlled parameter specifying the URL to retrieve. Because the server itself makes the request, it appears to originate from the local host, bypassing any access restrictions based on source IP or other client-side checks. The root cause is a lack of proper input validation and origin verification within the mainframeset.cfm application, allowing an attacker to craft a malicious URL that targets internal or restricted resources. This is a classic example of SSRF due to the server's trust in user-supplied input.