CVE-2019-8293 in upload-image-with-ajax
Summary
by MITRE
Due to a logic error in the code, upload-image-with-ajax v1.0 allows arbitrary files to be uploaded to the web root allowing code execution.
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Analysis
by VulDB Data Team • 03/16/2024
The vulnerability identified as CVE-2019-8293 affects the upload-image-with-ajax plugin version 1.0, representing a critical security flaw that stems from inadequate input validation mechanisms within the file upload functionality. This issue manifests as a logic error in the backend code that fails to properly restrict file types during the upload process, creating an avenue for malicious actors to bypass intended security controls. The vulnerability resides in the plugin's file handling routines where the system does not adequately verify the file extensions or content types before storing uploaded files to the web root directory, thereby enabling unauthorized file placement that could contain malicious code.
The technical implementation of this vulnerability allows attackers to upload arbitrary file types without proper authorization or validation checks. When users interact with the plugin's upload interface, the system accepts files regardless of their extension or content, failing to enforce proper file type restrictions that would normally prevent execution of potentially harmful code. The flaw specifically occurs in the server-side processing logic where the plugin does not implement robust sanitization or validation procedures, creating a direct path for code execution through the web root directory. This logic error essentially removes all barriers between the user's file upload request and the actual storage of that file on the web server, enabling attackers to place executable files such as php, aspx, or other script files directly into the web accessible directory.
The operational impact of this vulnerability is severe and encompasses multiple attack vectors that can lead to complete system compromise. An attacker who successfully exploits this vulnerability can execute arbitrary code on the target system, potentially gaining full administrative control over the web server. The ability to upload malicious files directly to the web root means that attackers can deploy web shells, backdoors, or other malicious payloads that persist across server restarts and can be used for ongoing unauthorized access. This vulnerability directly maps to CWE-434 which describes insecure file upload vulnerabilities where the application accepts files without proper validation, and aligns with ATT&CK technique T1190 which covers exploit for lateral movement through the use of compromised web applications. The impact extends beyond simple code execution to include data exfiltration, system enumeration, and potential use as a foothold for broader network infiltration.
Mitigation strategies for CVE-2019-8293 require immediate implementation of multiple defensive measures to address the core logic flaw. System administrators should first disable or remove the vulnerable plugin from affected systems until a patched version is available, as this represents a critical security risk that should not be left unaddressed. The recommended approach involves implementing strict file type validation that checks both the file extension and MIME type against a whitelist of approved formats, combined with content-based verification to ensure uploaded files match their claimed types. Additionally, the web server configuration should be adjusted to prevent execution of files in the upload directory, and proper file permissions should be enforced to limit write access to necessary components only. Organizations should also implement network monitoring to detect suspicious file upload activities and establish regular security audits to identify similar logic errors in other components. The vulnerability demonstrates the critical importance of input validation and proper access controls, aligning with security best practices outlined in NIST SP 800-53 and OWASP Top Ten category A01:2021 which emphasizes the need for secure file handling mechanisms to prevent unauthorized code execution.