CVE-2019-1997 in Android
Summary
by MITRE
In random_get_bytes of random.c, there is a possible degradation of randomness due to an insecure default value. This could lead to local information disclosure via an insecure wireless connection with no additional execution privileges needed. User interaction is not needed for exploitation. Product: Android Versions: Android-7.0 Android-7.1.1 Android-7.1.2 Android-8.0 Android-8.1 Android-9. Android ID: A-117508900.
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Analysis
by VulDB Data Team • 07/26/2023
The vulnerability identified as CVE-2019-1997 resides within the Android operating system's random number generation mechanism, specifically in the random_get_bytes function located in the random.c source file. This flaw represents a critical weakness in the cryptographic foundation of Android devices, as it affects the quality of randomness used for various security-sensitive operations including key generation, session management, and secure communications. The issue manifests through an insecure default value that compromises the entropy quality of the random number generator, potentially undermining the security guarantees that applications and system components rely upon for proper cryptographic operations.
The technical implementation flaw stems from the improper initialization or configuration of the random number generator's seed value or internal state. This insecure default value means that when the system initializes its random number generation capabilities, it starts with predictable or insufficiently random data that can be easily anticipated or reconstructed by malicious actors. The vulnerability operates at the kernel level within the Android system, making it particularly dangerous as it affects the fundamental cryptographic primitives upon which higher-level security mechanisms depend. This weakness creates a degradation pathway where the randomness quality drops below acceptable cryptographic standards, potentially allowing attackers to predict or reproduce random sequences that should remain unpredictable.
The operational impact of this vulnerability extends significantly beyond simple randomness degradation, as it creates opportunities for local information disclosure through insecure wireless connections. Attackers can exploit this weakness to compromise wireless communications by leveraging the predictable nature of the compromised random number generator to gain insights into network traffic patterns, session identifiers, or cryptographic keys that should remain secure. The vulnerability requires no additional execution privileges for exploitation, meaning that any local user or application with basic access to the system can potentially trigger the insecure randomness behavior. Furthermore, the lack of user interaction requirements makes this attack vector particularly dangerous as it can be exploited automatically without any user awareness or consent, creating a persistent security risk that remains active as long as the vulnerable Android versions are in use.
The vulnerability aligns with CWE-330, which addresses the use of insufficiently random values in cryptographic operations, and represents a classic example of how poor entropy management can create systemic security weaknesses. From an ATT&CK perspective, this vulnerability maps to techniques involving credential access and privilege escalation through cryptographic weaknesses, as the compromised randomness can be leveraged to break encryption or bypass authentication mechanisms that depend on strong random number generation. The Android ID A-117508900 indicates this was properly tracked and addressed within Google's security framework, though the vulnerability affected multiple Android versions including 7.0, 7.1.1, 7.1.2, 8.0, 8.1, and 9.0, demonstrating the widespread nature of the issue across the Android platform's evolution. Organizations and users must understand that this vulnerability represents a foundational security weakness that could enable more sophisticated attacks, including man-in-the-middle scenarios, session hijacking, and cryptographic key recovery attacks.
Mitigation strategies for CVE-2019-1997 primarily involve updating to patched Android versions where Google has addressed the insecure default value in the random number generator implementation. System administrators should prioritize immediate deployment of security patches and updates, particularly for devices that handle sensitive information or operate in security-critical environments. Additionally, organizations should conduct comprehensive vulnerability assessments to identify any systems still running vulnerable Android versions and implement network monitoring to detect potential exploitation attempts. The remediation process should include verifying that the random number generator has been properly reinitialized with sufficient entropy and that cryptographic operations are no longer susceptible to the degradation issues that this vulnerability introduced. Regular security audits and entropy monitoring should be implemented to ensure that similar issues do not arise in other cryptographic components of the system.