CVE-2017-16870 in UpdraftPlus Plugin
Summary
by MITRE
The UpdraftPlus plugin through 1.13.12 for WordPress has SSRF in the updraft_ajax_handler function in /wp-content/plugins/updraftplus/admin.php via an httpget subaction.
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Analysis
by VulDB Data Team • 08/06/2024
The CVE-2017-16870 vulnerability represents a server-side request forgery flaw within the UpdraftPlus WordPress plugin, a widely used backup solution that has been installed on hundreds of thousands of websites. This vulnerability exists in versions through 1.13.12 and specifically targets the updraft_ajax_handler function located in the admin.php file. The flaw manifests through an httpget subaction parameter that allows malicious actors to manipulate the plugin's functionality to make unauthorized requests to internal or external systems. The vulnerability's impact extends beyond simple data exfiltration as it can be leveraged to perform reconnaissance activities, access internal network resources, and potentially escalate privileges within the compromised environment.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the plugin's AJAX handler. When the updraft_ajax_handler function processes the httpget subaction, it fails to properly validate or sanitize the input parameters, allowing attackers to inject arbitrary URLs or network requests. This weakness aligns with CWE-918, which specifically addresses server-side request forgery vulnerabilities where applications fail to properly validate or sanitize user-supplied URLs or network requests. The flaw operates by accepting user-controllable input and directly using it in HTTP requests without adequate validation, creating an attack surface that can be exploited to bypass network security controls and access internal resources that should normally be protected from external access.
The operational impact of this vulnerability is significant for WordPress administrators and security teams managing sites with the affected plugin. Attackers can leverage this flaw to perform various malicious activities including internal port scanning to identify open services on the server's network, accessing internal APIs or web services that are not exposed to the public internet, and potentially exfiltrating sensitive data from internal systems. The vulnerability can be exploited through a simple HTTP request to the plugin's AJAX handler endpoint, making it relatively easy to discover and exploit. From an adversary perspective, this vulnerability maps to several ATT&CK techniques including T1071.004 for application layer protocol usage and T1046 for network service scanning, as it enables attackers to probe internal network configurations and identify potential targets for further exploitation.
Mitigation strategies for CVE-2017-16870 should focus on immediate plugin updates to versions that address the vulnerability, as the developers released patches to resolve the input validation issues. Organizations should also implement network-level restrictions to prevent internal network access from web applications where possible, and consider implementing web application firewalls to monitor and block suspicious requests to the plugin's AJAX handler. Security teams should conduct thorough audits of all installed WordPress plugins to identify similar vulnerabilities, particularly those that handle user input in HTTP request contexts. The vulnerability highlights the importance of input validation and the principle of least privilege in web application development, where applications should never trust user input and should always validate and sanitize all external data before processing. Regular security assessments and penetration testing should include checks for similar server-side request forgery vulnerabilities in third-party WordPress plugins, as these represent common attack vectors that can provide adversaries with significant access to compromised environments.