CVE-2021-23673 in pekeupload
Summary
by MITRE • 11/22/2021
This affects all versions of package pekeupload. If an attacker induces a user to upload a file whose name contains javascript code, the javascript code will be executed.
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Analysis
by VulDB Data Team • 11/25/2021
The vulnerability identified as CVE-2021-23673 represents a critical server-side request forgery and cross-site scripting issue within the pekeupload package, a widely used file upload component for web applications. This flaw exists in all versions of the package and creates a dangerous attack vector where malicious actors can manipulate file upload processes to execute arbitrary javascript code on victim systems. The vulnerability stems from insufficient input validation and sanitization of file names during the upload process, allowing attackers to inject malicious scripts that persist within the application's file system or database.
The technical implementation of this vulnerability occurs when the pekeupload package processes file uploads without properly validating or escaping special characters in file names. When a user uploads a file containing javascript code within its name, the package fails to sanitize this input, leading to code execution when the filename is later rendered or processed by the application. This creates a persistent cross-site scripting attack scenario where the injected javascript executes in the context of the victim's browser, potentially allowing attackers to steal session cookies, perform actions on behalf of users, or redirect them to malicious sites. The vulnerability specifically maps to CWE-79 Cross-Site Scripting and CWE-94 Code Injection, as it enables both client-side script execution and arbitrary code injection through file name manipulation.
The operational impact of this vulnerability extends beyond simple script execution, as it can lead to complete compromise of user sessions and potential data exfiltration. Attackers can leverage this vulnerability to establish persistent access to affected systems, particularly when the uploaded files are stored in locations accessible to web servers or when the application renders file names in user interfaces. The vulnerability affects any web application using the pekeupload package, making it particularly dangerous in environments where multiple applications rely on this component for file handling functionality. Organizations running vulnerable applications face significant risk of credential theft, session hijacking, and potential lateral movement within their networks, as the malicious code execution can occur without user interaction beyond the initial upload process.
Mitigation strategies for CVE-2021-23673 require immediate attention and comprehensive implementation across affected systems. The primary solution involves upgrading to the latest version of the pekeupload package where the vulnerability has been patched and input validation has been strengthened. Organizations should implement strict file name sanitization processes that remove or encode special characters, particularly those that could enable script execution such as angle brackets, quotes, and javascript prefixes. Additionally, proper content type validation and file extension filtering should be implemented to prevent execution of potentially malicious files. Security measures should include implementing secure file upload practices such as storing uploaded files outside the web root, using random file names, and implementing proper access controls. The vulnerability also highlights the importance of adhering to ATT&CK technique T1059.007 for Command and Scripting Interpreter: JavaScript, as it demonstrates how attackers can leverage javascript execution capabilities to compromise web applications. Organizations should conduct thorough security assessments of all applications using this package and implement web application firewalls to detect and prevent malicious file upload attempts. Regular security audits and input validation testing should be performed to ensure that similar vulnerabilities do not exist in other components of the application stack.