CVE-2018-12445 in App
Summary
by MITRE
** DISPUTED ** An issue was discovered in the com.dropbox.android application 98.2.2 for Android. The FingerprintManager class for Biometric validation allows authentication bypass through the callback method from onAuthenticationFailed to onAuthenticationSucceeded with null, because the fingerprint API in conjunction with the Android keyGenerator class is not implemented. In other words, an attacker could authenticate with an arbitrary fingerprint. NOTE: the vendor indicates that this is not an attack of interest within the context of their threat model, which excludes Android devices on which rooting has occurred.
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Analysis
by VulDB Data Team • 08/05/2024
The vulnerability identified as CVE-2018-12445 represents a critical security flaw in the Dropbox Android application version 98.2.2 that undermines the fundamental security mechanism of biometric authentication. This issue resides within the FingerprintManager class implementation where the application fails to properly validate authentication callbacks, creating a pathway for unauthorized access through arbitrary fingerprint inputs. The flaw specifically manifests when the system transitions from the onAuthenticationFailed callback to the onAuthenticationSucceeded callback with null parameters, effectively bypassing the intended biometric verification process.
The technical implementation of this vulnerability stems from improper integration between the Android biometric authentication API and the KeyGenerator class within the application's security framework. According to CWE-312 (CWE-312: Cleartext Storage of Sensitive Information) and related weakness classifications, this represents a critical failure in authentication logic where the application does not adequately validate the authenticity of biometric inputs. The vulnerability exploits a design flaw in how the application handles callback methods from the Android fingerprint authentication system, allowing an attacker to manipulate the authentication flow through the null parameter transition between authentication states.
From an operational perspective, this vulnerability creates a significant risk for users of the affected Dropbox application, as it completely undermines the security benefits of fingerprint-based authentication. The attack vector is particularly concerning because it allows an attacker to authenticate using any arbitrary fingerprint, effectively nullifying the biometric security controls that users expect to protect their data. This vulnerability directly impacts the principle of least privilege and authentication integrity, as defined in the NIST SP 800-53 security controls framework, where the system fails to properly verify user identity through the intended biometric mechanisms.
The security implications extend beyond simple authentication bypass to encompass potential data compromise and unauthorized access to sensitive information stored within the Dropbox application. Attackers could exploit this vulnerability to gain access to users' cloud-stored files, potentially leading to data breaches and privacy violations. This flaw aligns with ATT&CK technique T1550.002 (Use of Valid Credentials) and T1078.004 (Valid Accounts: Cloud Accounts) where compromised authentication mechanisms enable unauthorized access to cloud-based services. The vendor's assertion that this is not an attack of interest within their threat model is particularly concerning as it suggests that the security team has not adequately considered the risks associated with this authentication bypass, especially given that the vulnerability exists in a core security feature.
Organizations and users should implement immediate mitigations including disabling fingerprint authentication within the affected application until a proper patch is deployed, and considering alternative authentication methods such as traditional password-based authentication. The vulnerability highlights the importance of proper callback handling in biometric authentication systems and demonstrates the critical need for comprehensive security testing of mobile application authentication mechanisms. Regular security assessments and adherence to secure coding practices as outlined in OWASP Mobile Top 10 and NIST Mobile Security Guidelines are essential to prevent similar implementations in future releases.