CVE-2018-6903 in Hot Scripts Clone Script Classified
Summary
by MITRE
PHP Scripts Mall Hot Scripts Clone Script Classified v3.1 uses the client side to enforce validation of an e-mail address, which allows remote attackers to modify a registered e-mail address by removing the validation code.
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Analysis
by VulDB Data Team • 03/18/2020
The vulnerability identified as CVE-2018-6903 resides within PHP Scripts Mall Hot Scripts Clone Script Classified v3.1, a web application designed for creating classified advertising platforms. This particular flaw represents a critical security oversight in the application's user registration and email verification process, where the system relies entirely on client-side validation mechanisms rather than implementing proper server-side checks. The vulnerability stems from the application's improper handling of email address validation, creating an exploitable condition that directly compromises user account integrity and potentially enables unauthorized access to sensitive user data.
The technical flaw manifests as a client-side validation bypass vulnerability that allows remote attackers to manipulate email address registration data without proper server-side verification. The application's design places the responsibility for email validation entirely on the client-side, typically implemented through javascript or html form validation mechanisms. This approach fails to enforce any server-side validation checks, meaning that malicious users can bypass the entire email verification process by simply modifying the client-side validation code or directly submitting requests to the server without proper email address formatting. The vulnerability specifically allows attackers to remove validation codes from email addresses, effectively enabling them to register or modify email addresses without completing the required verification steps.
The operational impact of this vulnerability extends beyond simple account manipulation and represents a significant threat to user privacy and platform security. Attackers can exploit this weakness to register multiple accounts using invalid or malicious email addresses, potentially enabling spamming activities, account takeover attempts, or fraudulent transactions within the classified advertising platform. The bypass of email verification creates opportunities for malicious actors to gain unauthorized access to user accounts, as many platforms use email verification as a primary method for account recovery and security confirmation. Additionally, the vulnerability undermines the platform's trust model, as users may receive spam or malicious communications due to the inability to verify legitimate email addresses.
This vulnerability aligns with CWE-642, which describes weaknesses where insufficient validation occurs on the server-side, allowing client-side controls to be bypassed. The flaw also corresponds to ATT&CK technique T1566, which covers social engineering attacks through spearphishing or other manipulation techniques, as attackers can exploit this vulnerability to manipulate user accounts through email address modification. The attack vector represents a classic example of insufficient server-side validation, where client-side controls are treated as security mechanisms rather than user experience enhancements. Security professionals should note that this vulnerability type is particularly dangerous because it often goes undetected during routine security assessments, as the client-side validation may appear to function correctly while the underlying server-side implementation remains insecure.
Mitigation strategies should focus on implementing robust server-side email validation mechanisms that cannot be bypassed through client-side manipulation. Organizations should enforce mandatory server-side verification of all email addresses before allowing account registration or modification, utilizing proper email validation libraries and implementing multiple verification steps including confirmation emails with unique tokens. The application architecture should be redesigned to ensure that all user data modifications, particularly email addresses, require proper server-side validation and verification before being accepted. Additionally, comprehensive input sanitization and validation should be implemented at all entry points, with proper logging and monitoring of email address changes to detect potential abuse attempts. Regular security testing including penetration testing and code reviews should be conducted to identify similar client-side validation bypass vulnerabilities in the application's codebase.