CVE-2020-8792 in Mobile Companion App
Summary
by MITRE
The OKLOK (3.1.1) mobile companion app for Fingerprint Bluetooth Padlock FB50 (2.3) has an information-exposure issue. In the mobile app, an attempt to add an already-bound lock by its barcode reveals the email address of the account to which the lock is bound, as well as the name of the lock. Valid barcode inputs can be easily guessed because barcode strings follow a predictable pattern. Correctly guessed valid barcode inputs entered through the app interface disclose arbitrary users' email addresses and lock names.
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Analysis
by VulDB Data Team • 05/05/2020
The vulnerability identified as CVE-2020-8792 represents a critical information disclosure flaw within the OKLOK mobile companion application version 3.1.1 designed for the Fingerprint Bluetooth Padlock FB50 model 2.3. This security weakness fundamentally compromises user privacy and system integrity by exposing sensitive account information through an overly permissive validation mechanism. The flaw manifests when users attempt to add a lock that has already been paired with an account, creating an information leak that reveals not only the associated email address but also the lock's name. This vulnerability falls under the CWE-200 category of Information Exposure, which specifically addresses the unintentional disclosure of information that could aid attackers in further compromising systems or users.
The technical implementation of this vulnerability stems from predictable barcode generation patterns that allow attackers to easily guess valid barcode inputs. The mobile application's validation process lacks proper access controls and authentication checks, enabling any user with knowledge of the barcode structure to exploit this weakness. The predictable nature of barcode strings means that an attacker can systematically generate valid inputs without requiring prior knowledge of specific account details. This design flaw creates a direct pathway for unauthorized information retrieval, as the application responds to valid barcode inputs with sensitive account metadata regardless of whether the requesting user has proper authorization to access that information. The vulnerability directly violates the principle of least privilege and demonstrates poor input validation practices that are commonly addressed in secure coding guidelines.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable more sophisticated attacks including account takeover attempts, social engineering campaigns, and targeted phishing operations. An attacker who successfully exploits this vulnerability gains access to email addresses of legitimate users, which can be used for credential stuffing attacks across other platforms where users may have reused passwords. The disclosure of lock names provides additional context that could be leveraged in more convincing social engineering attacks or to understand the security landscape of specific users. This information exposure creates a significant risk for users who may have linked their accounts to other services, potentially enabling cascading security breaches that extend far beyond the initial compromised device. The vulnerability particularly affects users who may have less technical sophistication and are more susceptible to targeted attacks using the disclosed information.
Mitigation strategies for this vulnerability should focus on implementing robust access controls and authentication mechanisms within the mobile application's barcode validation process. The application should require proper user authentication before responding to barcode inputs, ensuring that only authorized account holders can access information about locks they own. Input validation should be strengthened to prevent predictable pattern exploitation, and the system should implement rate limiting to prevent automated guessing attacks. Additionally, the application should not disclose account-specific information in response to barcode validation requests, instead requiring explicit account authentication before providing any sensitive data. Security measures should include proper error handling that does not reveal whether a barcode is valid or invalid, and implementing cryptographic protections for sensitive data. Organizations should also consider implementing monitoring and alerting mechanisms to detect unusual patterns of barcode validation attempts that might indicate exploitation attempts. These measures align with the ATT&CK framework's defense in depth principles and help protect against information disclosure threats that could lead to more severe security incidents.