CVE-2023-1385 in Fire TV Stick 3rd Gen
Summary
by MITRE • 05/03/2023
Improper JPAKE implementation allows offline PIN brute-forcing due to the initialization of random values to a known value, which leads to unauthorized authentication to amzn.lightning services.
This issue affects:
Amazon Fire TV Stick 3rd gen versions prior to 6.2.9.5. Insignia TV with FireOS 7.6.3.3.
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Analysis
by VulDB Data Team • 05/27/2023
The vulnerability identified as CVE-2023-1385 represents a critical weakness in the Java Persistent API Key Exchange (JPAKE) implementation used by Amazon's lightning services. This flaw stems from improper cryptographic randomization where the system initializes random values to predetermined known values instead of utilizing truly random seeds. The vulnerability specifically impacts the authentication mechanisms of Amazon Fire TV devices running affected firmware versions, creating a pathway for unauthorized access to protected services. The JPAKE protocol is designed to establish secure cryptographic sessions through key exchange, but when random values become predictable, it fundamentally undermines the security assurances that should protect user authentication.
The technical implementation flaw manifests in the cryptographic library's failure to properly initialize random number generators during the JPAKE key exchange process. This weakness allows attackers to perform offline brute-force attacks against PIN authentication systems by exploiting the predictable nature of the random values. When random values are initialized to known constants rather than genuine entropy sources, the cryptographic strength of the authentication mechanism is severely compromised. The vulnerability's impact extends to the broader Amazon Lightning service ecosystem, where users may be able to bypass authentication mechanisms through repeated brute-force attempts against the predictable random values. This issue directly relates to CWE-330, which addresses the use of insufficiently random values in cryptographic contexts, and represents a clear violation of cryptographic best practices for secure key exchange protocols.
The operational impact of this vulnerability creates significant security risks for users of affected Amazon Fire TV devices, as it enables unauthorized access to premium content and services without proper authentication. Attackers can exploit this weakness to perform offline PIN brute-force attacks, potentially gaining access to user accounts, subscription services, and other protected content. The vulnerability affects specific hardware generations including the Amazon Fire TV Stick 3rd generation and certain Insignia TVs running FireOS 7.6.3.3, representing a substantial user base that could be compromised. This weakness particularly affects the authentication flows within Amazon's ecosystem, where the JPAKE implementation should provide secure session establishment but instead creates predictable cryptographic states that can be exploited. The vulnerability's persistence across multiple device types indicates a systemic issue in the cryptographic implementation rather than an isolated device-specific problem.
Mitigation strategies for CVE-2023-1385 require immediate firmware updates from Amazon to address the random number generation implementation in the JPAKE protocol. Users should ensure their devices are updated to versions 6.2.9.5 or later, which contain the necessary cryptographic fixes. Organizations should implement monitoring for suspicious authentication attempts and consider network-level controls to prevent unauthorized access attempts. The fix should ensure that all random number generators are properly seeded with sufficient entropy before cryptographic operations begin, preventing the predictable random values that enable brute-force attacks. Security teams should also review other implementations of JPAKE and similar protocols within their environments to identify similar weaknesses. This vulnerability demonstrates the critical importance of proper random number generation in cryptographic systems and aligns with ATT&CK technique T1110.003 for credential access through brute force attacks. The remediation process should include comprehensive testing of cryptographic implementations to ensure that random values are properly initialized and that the security properties of the key exchange protocol are maintained throughout the authentication process.