CVE-2018-20101 in Import Users from CSV with Meta Plugin
Summary
by MITRE
The codection "Import users from CSV with meta" plugin before 1.12.1 for WordPress allows XSS via the value of a cell.
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Analysis
by VulDB Data Team • 04/20/2020
The vulnerability identified as CVE-2018-20101 affects the codection "Import users from CSV with meta" plugin for WordPress, specifically versions prior to 1.12.1. This security flaw represents a cross-site scripting vulnerability that arises from improper input validation and sanitization within the plugin's CSV import functionality. The issue occurs when the plugin processes user data from CSV files, particularly when handling cell values that contain malicious script content. The vulnerability is categorized under CWE-79, which specifically addresses Cross-Site Scripting flaws in software applications. The plugin's failure to properly sanitize user-supplied data during the import process creates an environment where attackers can inject malicious scripts that execute in the context of other users' browsers.
The technical implementation of this vulnerability stems from the plugin's lack of proper output encoding and input validation mechanisms when processing CSV data containing user information. When administrators or users upload CSV files through the import functionality, the plugin directly incorporates cell values into the web page without appropriate sanitization measures. This creates a persistent XSS vector where malicious payloads can be stored in the database and subsequently executed whenever affected pages are loaded. The vulnerability is particularly concerning because it leverages the plugin's legitimate import functionality to deliver malicious scripts, making it difficult to distinguish between legitimate and malicious data. Attackers can exploit this by crafting CSV files containing script tags or other malicious code within user data fields, which then get executed when the imported user data is displayed on WordPress admin pages or user profiles.
The operational impact of CVE-2018-20101 extends beyond simple script execution, as it can enable attackers to perform various malicious activities including credential theft, session hijacking, and data exfiltration. When exploited, the vulnerability allows unauthorized parties to inject scripts that can capture user credentials, steal session cookies, or redirect users to malicious websites. The attack surface is broad since the vulnerability affects WordPress administrators who might import user data from external sources, including potentially compromised third-party CSV files. The vulnerability also aligns with ATT&CK technique T1566.001, which involves the use of malicious content to gain initial access to systems through social engineering attacks that leverage the trust placed in legitimate import processes. Additionally, the vulnerability can facilitate privilege escalation attacks when administrators with elevated privileges import malicious CSV data, as the executed scripts can operate with the privileges of the affected user accounts.
Organizations using vulnerable versions of this plugin should immediately implement mitigation strategies including updating to version 1.12.1 or later, which contains proper input validation and output sanitization measures. Administrators should also review existing user data imports for potential malicious content and consider implementing additional security controls such as web application firewalls that can detect and block suspicious script content. The vulnerability demonstrates the importance of proper input validation and output encoding practices in web applications, particularly in plugins that handle user-supplied data. Security teams should also monitor for exploitation attempts through log analysis and implement principle of least privilege access controls to limit the impact of potential successful attacks. This vulnerability serves as a reminder of the critical need for comprehensive security testing of WordPress plugins, particularly those that process external data inputs, and underscores the necessity of maintaining up-to-date software versions to protect against known vulnerabilities.