CVE-2021-20751 in EC-CUBE
Summary
by MITRE • 06/28/2021
Cross-site scripting vulnerability in EC-CUBE EC-CUBE 4.0.0 to 4.0.5-p1 (EC-CUBE 4 series) allows a remote attacker to inject an arbitrary script by leading an administrator or a user to a specially crafted page and to perform a specific operation.
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Analysis
by VulDB Data Team • 07/03/2021
This cross-site scripting vulnerability exists within the EC-CUBE e-commerce platform version 4.0.0 through 4.0.5-p1, representing a critical security flaw that enables remote attackers to execute malicious scripts against unsuspecting users. The vulnerability stems from insufficient input validation and output encoding mechanisms within the application's web interface, particularly affecting the administrative dashboard and user-facing components. Attackers can craft malicious web pages containing malicious script code that, when visited by administrators or regular users, executes within their browser context. This flaw operates as a classic reflected cross-site scripting vulnerability where user-supplied data is not properly sanitized before being rendered back to the browser. The attack typically requires social engineering to convince targets to click on malicious links or visit compromised web pages, making it particularly dangerous in environments where administrators frequently navigate to external sites. The vulnerability allows attackers to potentially steal session cookies, perform unauthorized actions on behalf of users, redirect victims to malicious sites, or extract sensitive information from the target's browser environment. This issue directly maps to CWE-79 which categorizes cross-site scripting flaws as weaknesses in input validation and output encoding. The attack vector aligns with ATT&CK technique T1566 which describes social engineering tactics used to gain initial access to target systems. The impact extends beyond simple script execution as it can lead to complete account compromise, data exfiltration, and potential lateral movement within the affected network. The vulnerability affects the core functionality of the EC-CUBE platform's user authentication and administrative interfaces, making it particularly dangerous for online stores that handle sensitive customer data and financial transactions. The affected versions represent a specific release series where proper security controls were not adequately implemented, highlighting the importance of input sanitization and output encoding practices in web applications. Organizations running these vulnerable versions face significant risk of unauthorized access and data breaches, especially when administrators are targeted due to their elevated privileges within the system. The exploitation requires minimal technical skill and can be automated, making it a particularly attractive attack vector for threat actors seeking to compromise e-commerce platforms. The vulnerability demonstrates the critical importance of maintaining up-to-date software versions and implementing proper security controls such as content security policies and input validation mechanisms to prevent such attacks from succeeding.
The technical implementation of this vulnerability occurs when user-provided data flows through the application's processing pipeline without adequate sanitization before being rendered in web pages. The affected EC-CUBE versions fail to properly encode or escape special characters in user inputs, allowing attackers to inject malicious script code that executes when the page loads. This typically manifests when administrators or users interact with malformed URLs or form submissions containing malicious payloads that bypass existing security controls. The vulnerability is particularly concerning because it affects both user and administrator interfaces, meaning that a successful attack could compromise either role depending on who visits the malicious page. Security controls such as HTTPOnly cookies, XSS filters, and proper input validation should have prevented this attack scenario but were either missing or insufficient in the affected software versions. The attack chain involves the attacker creating a malicious URL or webpage that, when accessed by an administrator, triggers the execution of the injected script code. This script could then steal session tokens, redirect users to phishing sites, or perform other malicious activities that leverage the privileges of the compromised user. The vulnerability's persistence and impact are amplified by the fact that administrators often have elevated privileges and access to sensitive system information, making successful exploitation particularly damaging. Organizations should immediately assess their deployment of these vulnerable versions and implement emergency patches or mitigations to prevent potential exploitation attempts. The vulnerability also highlights the need for comprehensive security testing and code review processes that specifically target input validation and output encoding controls in web applications. Proper implementation of security measures such as the OWASP Top 10 prevention guidelines and regular security assessments would have identified and mitigated this vulnerability before it could be exploited in the wild.