CVE-2023-27451 in Instant Images Plugin
Summary
by MITRE • 11/22/2023
Server-Side Request Forgery (SSRF) vulnerability in Darren Cooney Instant Images plugin <= 5.1.0.2 versions.
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Analysis
by VulDB Data Team • 12/15/2023
The CVE-2023-27451 vulnerability represents a critical server-side request forgery flaw discovered in the Instant Images plugin for WordPress, affecting versions up to and including 5.1.0.2. This vulnerability resides within the plugin's handling of remote image processing requests, where the application fails to properly validate or sanitize user-supplied URLs that are used to fetch external resources. The flaw allows an attacker to manipulate the plugin's functionality to make unauthorized requests to internal network resources or external malicious servers, potentially exposing sensitive information or enabling further exploitation.
The technical implementation of this vulnerability stems from inadequate input validation mechanisms within the plugin's image processing pipeline. When users upload or process images through the plugin's interface, the system accepts remote URLs without sufficient sanitization checks. This weakness creates an environment where malicious actors can craft specially formatted URLs that bypass normal network restrictions and access internal systems that should remain isolated from external threats. The vulnerability specifically targets the plugin's ability to fetch images from remote sources, making it particularly dangerous in environments where WordPress installations have access to internal network resources.
From an operational impact perspective, this vulnerability presents significant risks to WordPress installations using the affected plugin version. Attackers can leverage the SSRF flaw to enumerate internal network services, access sensitive data stored on internal servers, or redirect requests to malicious endpoints for phishing attacks. The vulnerability may also enable attackers to bypass network security controls such as firewalls and intrusion detection systems that typically protect internal network segments. In multi-tenant hosting environments or enterprise deployments, this could lead to unauthorized access to other customer data or internal infrastructure components, potentially resulting in data breaches or service disruption.
Security professionals should consider this vulnerability in the context of the CWE-918 weakness classification, which specifically addresses server-side request forgery vulnerabilities in web applications. The ATT&CK framework categorizes this issue under T1190 - Proxy Trojan, where attackers establish connections to internal resources through compromised web applications. Mitigation strategies should include immediate plugin updates to versions that address the vulnerability, implementation of network-level restrictions to prevent outbound requests to internal resources, and thorough input validation of all user-supplied URLs. Organizations should also consider implementing web application firewalls to detect and block suspicious requests, while conducting comprehensive security assessments to identify any potential exploitation attempts that may have occurred prior to patching.