Under Construction, Coming Soon & Maintenance Mode Server-Side Request Forgery (SSRF) Scanner

The Under Construction, Coming Soon & Maintenance Mode plugin is a widely deployed WordPress tool, used mainly by website administrators and developers. The plugin allows users to easily set their site into maintenance mode, displaying a friendly notice when visitors try to access the site. It is often employed during site updates, redesigns, or initial construction phases to keep aspects of the development work private. Popular among both small business owners and larger enterprises, this plugin ensures that a professional appearance is maintained even when full site access is temporarily rescinded. The tool's simplicity and effectiveness make it a staple for those who want to ensure their site is always properly presented to the public. Regular updates and active support further enhance its reliability and appeal among WordPress users.

Server Side Request Forgery (SSRF) is a type of web security vulnerability that allows an attacker to induce the server-side application to make HTTP requests to an arbitrary domain of the attacker's choosing. SSRF vulnerabilities can often enable a malicious actor to bypass firewalls, access internal-only services, and sometimes exploit sensitive data from within the company's data stores. In this specific scenario, an unvalidated input is used to construct a URL that is later called by the server, leading to the potential exploitation of server-side resources. Attackers can exploit this flaw to cause the server to make requests to internal services not accessible to clients. By manipulating input, they may direct the server to leak services on the internal network or access endpoints the server shouldn't normally interact with.

The vulnerability in Under Construction, Coming Soon & Maintenance Mode plugin is found in the includes/mc-get_lists.php component. The vulnerability is triggered due to the use of an unsanitized 'apiKey' POST parameter, which is used to create an HTTPS URL that gets invoked via cURL. The improperly sanitized parameter allows for Server Side Request Forgery via direct access and through an AJAX call named ucmm_mc_api. This call is exposed to both authenticated and unauthenticated users, making the attack vector especially concerning. By crafting specific inputs, a malicious actor can utilize this parameter to make requests to unintended servers, thereby exploiting network resources or accessing unauthorized data.

If exploited, the SSRF vulnerability in this plugin could have serious repercussions. Attackers might leverage it to expose confidential backend services, which could lead to data theft or manipulation. The exposure of sensitive information in backend systems could compromise privacy, potentially affecting compliance with legal standards. Furthermore, SSRF can be a stepping stone in larger attack chains, allowing attackers to conduct reconnaissance on internal networks. Consequently, the exploitation of such vulnerabilities could jeopardize the entire network structure, leading to widespread damage and financial loss.

REFERENCES

• https://wpscan.com/vulnerability/24784c84-3efd-4166-81c1-e5a266562cfc
• https://packetstormsecurity.com/files/161576/