Source: cna@vuldb.com
A flaw has been found in go-sonic sonic up to 1.1.4. The affected element is the function FetchTheme of the file service/theme/git_fetcher.go of the component Theme Fetching API. Executing manipulation of the argument uri can lead to server-side request forgery. The attack may be launched remotely. The exploit has been published and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
go-sonic sonic versions up to 1.1.4 are vulnerable to a Server-Side Request Forgery (SSRF) attack. This allows attackers to make unauthorized requests from the server, potentially leading to sensitive data exposure or internal network compromise. The vulnerability is easily exploitable due to a published proof-of-concept and lack of vendor response.
Step 1: Payload Delivery: The attacker crafts a malicious URI, such as http://internal-service:8080/sensitive-data or file:///etc/passwd, and submits it as the uri argument to the FetchTheme function.
Step 2: Request Execution: The FetchTheme function, without proper validation, uses the attacker-controlled URI to initiate an HTTP request.
Step 3: Data Retrieval/Interaction: The server, acting on behalf of the attacker, makes the request to the specified URI. This could be an internal service, a local file, or an external server.
Step 4: Information Leakage/Exploitation: The response from the target (internal service, file, etc.) is then either returned to the attacker (in the case of an external server) or, if the attacker can control the response, used to further exploit the system. This could lead to data exfiltration, service disruption, or further compromise.
The vulnerability lies within the FetchTheme function in service/theme/git_fetcher.go. This function, part of the Theme Fetching API, is responsible for retrieving themes from a specified URI. The root cause is a lack of proper input validation and sanitization of the uri argument. Specifically, the function fails to validate the destination of the URI, allowing an attacker to specify an internal or external address. This allows an attacker to control the destination of the HTTP request made by the server. This can be exploited to access internal services, bypass firewall restrictions, or potentially leak sensitive information.
While no specific APTs are directly linked, the ease of exploitation and potential for internal network access makes this vulnerability attractive to a wide range of attackers. This vulnerability could be leveraged by ransomware groups for initial access. CISA KEV: Not applicable at this time, but likely to be added soon given the public PoC and lack of vendor response.
Monitor server logs for unusual HTTP requests originating from the go-sonic sonic service, especially those targeting internal IP addresses or unusual ports.
Analyze network traffic for outbound HTTP requests from the go-sonic sonic server to suspicious or unexpected destinations.
Examine the uri parameter in requests to the FetchTheme API for malicious patterns, such as internal IP addresses, file paths (e.g., file:///), or unusual protocols.
Implement a Web Application Firewall (WAF) rule to block requests containing potentially malicious URIs in the uri parameter.
Upgrade to go-sonic sonic version 1.1.5 or later (if available) that addresses the vulnerability. (Note: The vendor's lack of response suggests this may not be a viable option).
Implement robust input validation and sanitization for the uri parameter in the FetchTheme function. This should include whitelisting allowed protocols (e.g., https) and validating the destination hostname/IP address.
Restrict the go-sonic sonic service's network access to only the necessary external resources. This can be achieved through firewall rules and network segmentation.
Implement a Web Application Firewall (WAF) to filter malicious requests.
Regularly scan the system for known vulnerabilities and apply security patches promptly.
Consider disabling the Theme Fetching API if it's not essential for the application's functionality.