Introduction
WordPress, the most widely used content management system (CMS) in the world, powers millions of websites across different industries. However, being an open-source platform, WordPress is not immune to vulnerabilities that can compromise the security of a website and its users. WordPress Core vulnerabilities are one of the most critical and damaging types of vulnerabilities that can occur within the core of the WordPress software itself. These vulnerabilities can be exploited by attackers to gain unauthorized access, steal sensitive information, or even take control of the entire website. In this article, we will delve into the topic of WordPress Core vulnerabilities, the potential risks and impacts they can cause, and the steps that can be taken to detect and prevent them. Keeping your WordPress website secure and protected is essential and understanding these types of vulnerabilities is a crucial step towards achieving this.
What is SSRF?

Server-Side Request Forgery (SSRF) is a web security vulnerability that allows an attacker to send a malicious request from a server, in order to access resources that are not normally accessible. This is done by tricking the server into making a request to an arbitrary URL, including internal network resources that are not intended to be accessed from outside the network.
An attacker can exploit SSRF vulnerability to access sensitive data such as internal network configurations, retrieve files from internal servers, or even access other systems through various protocol handlers. They can also leverage SSRF vulnerability to perform various other types of attacks such as port scanning, fuzzing and even DDoS attack.
This vulnerability is often found in web application that can make HTTP requests and the attacker can control the URL used in the request. Common example include web applications that use the HTTP client library to fetch external resources, such as an RSS feed, while also allowing a user to specify the URL of the resource to be fetched.
Preventing SSRF vulnerabilities can be difficult, as it is often an architectural or design-level issue. However, there are some mitigation techniques such as implementing a whitelist of allowed external domains or IP addresses, validating input and sanitizing parameters, and using a firewall to block internal addresses from being accessed externally. Additionally, web application developers should be trained to understand the risks associated with SSRF vulnerabilities and must be aware of these risks when developing and testing their web applications.
The Vulnerability of WordPress Core Vulnerabilities
WordPress, one of the most widely used Content Management Systems (CMS), has recently been found to be affected by an unauthenticated blind Server-Side Request Forgery (SSRF) vulnerability in its pingback feature. This vulnerability is caused by a Time-of-Check-to-Time-of-Use (TOCTOU) race condition between the validation checks and the HTTP request, allowing attackers to reach internal hosts that were explicitly forbidden.
The pingback feature in WordPress allows a website to notify another website when it links to one of its posts. The vulnerability occurs when a malicious actor manipulates the pingback feature to send requests to internal hosts, bypassing the validation checks in place. This can enable the attacker to access sensitive information, steal data or launch DDoS attack.
The impact of this vulnerability can be severe for website owners and administrators, as it can potentially allow attackers to gain unauthorized access, steal sensitive information or even take control of the entire website. It is important to note that this vulnerability affects all versions of WordPress prior to 4.9.9 and 5.0.1.
To protect yourself from this vulnerability, it is crucial to update your WordPress installation to the latest version, immediately. Additionally, it is also recommended to use a web application firewall (WAF) that can detect and block SSRF attacks. Furthermore, always follow best practices such as input validation, sanitization, and encoding to secure your web application, as well as regularly updating the software and its plugins.
Finally, It’s always necessary to have an understanding of the risks and implications of security testing, and performing regular security assessments and penetration testing can help to ensure the security of your systems. Additionally, it is essential to test for other types of vulnerabilities in addition to SSRF vulnerabilities, as well as stay informed about new and emerging threats in the cybersecurity landscape by reading security blogs, attending security conferences, and participating in online security communities.