CVE-2017-5214 in B2J Contact Extension
Summary
by MITRE
The Codextrous B2J Contact (aka b2j_contact) extension before 2.1.13 for Joomla! allows prediction of a uniqid value based on knowledge of a time value. This makes it easier to read arbitrary uploaded files.
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Analysis
by VulDB Data Team • 09/30/2020
The Codextrous B2J Contact extension for Joomla! versions prior to 2.1.13 contains a critical cryptographic vulnerability that stems from predictable unique identifier generation. This weakness specifically affects the uniqid function implementation within the file upload mechanism, creating a scenario where attackers can forecast the unique identifiers used for uploaded files. The vulnerability arises from the predictable nature of the uniqid function when seeded with known time values, allowing adversaries to construct malicious requests that target specific files. This flaw directly violates security principles related to entropy and randomness in cryptographic operations, as outlined in CWE-330. The vulnerability is particularly concerning because it enables attackers to bypass normal access controls and read arbitrary files that should otherwise remain protected, creating a path for unauthorized data access and potential information disclosure.
The technical implementation of this vulnerability occurs within the extension's file handling code where uniqid values are generated to name uploaded files. When an attacker can determine or predict the time component used to seed the uniqid function, they gain the ability to calculate the exact filenames of uploaded files. This predictability allows for directory traversal attacks and arbitrary file reading exploits, as demonstrated in the context of the B2J Contact extension. The flaw represents a specific instance of weak random number generation that affects the security of file upload mechanisms, creating opportunities for privilege escalation and data exfiltration. According to ATT&CK framework, this vulnerability maps to T1078 (Valid Accounts) and T1566 (Phishing) as attackers can leverage predictable file names to gain unauthorized access to sensitive data that was intended to be protected through proper file naming conventions.
The operational impact of CVE-2017-5214 extends beyond simple information disclosure, as it enables attackers to systematically access uploaded files that may contain sensitive data such as user information, configuration details, or system credentials. The vulnerability essentially undermines the integrity of the file upload security model by providing attackers with a method to enumerate and access files that should remain private. This weakness can be exploited in conjunction with other vulnerabilities or through social engineering to maximize the damage potential. Organizations running affected Joomla! installations are particularly at risk as the B2J Contact extension is commonly used for contact forms and data collection, making it a prime target for attackers seeking to harvest user data or system information. The vulnerability's impact is amplified by the fact that it requires minimal reconnaissance to exploit, as the time-based predictability can often be determined through simple observation or network traffic analysis.
Mitigation strategies for this vulnerability require immediate patching of the B2J Contact extension to version 2.1.13 or later, where the predictable uniqid implementation has been corrected. System administrators should also implement additional security measures such as randomizing file naming conventions, implementing proper access controls, and monitoring file upload activities for suspicious patterns. The fix typically involves replacing the vulnerable uniqid function with a cryptographically secure random number generator that does not rely on predictable time components. Organizations should also consider implementing web application firewalls to detect and block exploitation attempts, along with regular security audits to identify similar vulnerabilities in other extensions or components. According to industry best practices for secure coding, this vulnerability highlights the importance of avoiding predictable sequences in security-critical applications and demonstrates the necessity of proper entropy sources in cryptographic implementations. The remediation process should include thorough testing to ensure that the updated implementation properly randomizes file identifiers and prevents future exploitation attempts.