CVE-2020-0187 in Android
Summary
by MITRE
In engineSetMode of BaseBlockCipher.java, there is a possible incorrect cryptographic algorithm chosen due to an incomplete comparison. This could lead to local information disclosure with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-10Android ID: A-148517383
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Analysis
by VulDB Data Team • 06/12/2020
The vulnerability identified as CVE-2020-0187 resides within the cryptographic implementation of Android's security framework, specifically in the BaseBlockCipher.java file where the engineSetMode method handles cryptographic algorithm selection. This flaw represents a critical weakness in the Android platform's cryptographic operations that could potentially compromise the confidentiality of sensitive data stored on devices. The vulnerability stems from an incomplete comparison logic that fails to properly validate the cryptographic mode selection, creating a scenario where the system might inadvertently choose an incorrect algorithm during cryptographic operations.
The technical flaw manifests in the engineSetMode method where the comparison logic used to validate cryptographic modes is insufficiently robust. When a cryptographic operation is initiated, the system evaluates various parameters to determine the appropriate algorithm and mode for execution. However, due to the incomplete comparison, certain invalid or unintended cryptographic modes may pass validation checks and be selected for use. This incomplete validation creates a path where the system could execute cryptographic operations using weaker or inappropriate algorithms, potentially exposing sensitive information. The vulnerability is classified under CWE-295 which specifically addresses improper certificate validation, though in this case the weakness manifests through algorithm selection rather than certificate handling.
The operational impact of this vulnerability extends beyond simple cryptographic weakness, as it creates a vector for local information disclosure attacks that require no additional privileges or user interaction. An attacker with local access to an Android device could exploit this vulnerability to potentially extract sensitive data that should be protected by cryptographic operations. The lack of requirement for user interaction or additional execution privileges makes this vulnerability particularly concerning as it can be exploited automatically without any user awareness or consent. The vulnerability affects Android 10 systems and is tracked under Android ID A-148517383, indicating its presence in the platform's core cryptographic libraries.
This vulnerability aligns with several ATT&CK framework techniques including T1552.001 (Unsecured Credentials) and T1552.004 (Credentials in Files) as it potentially exposes cryptographic keys or sensitive data that should remain protected. The incomplete comparison logic creates a situation where cryptographic operations may not provide the expected security guarantees, effectively weakening the cryptographic protection mechanisms that users rely on for data confidentiality. The vulnerability's classification as a local information disclosure threat means that even without network access or remote exploitation capabilities, an attacker can potentially access sensitive information stored on the device.
Mitigation strategies for CVE-2020-0187 should prioritize immediate system updates from Android security patches that address the incomplete comparison logic in the cryptographic mode selection process. Organizations should ensure that all Android 10 devices are updated to the latest security patches provided by Google, as these updates specifically address the flawed validation mechanism in BaseBlockCipher.java. Additionally, security monitoring should be implemented to detect any anomalous cryptographic operations that might indicate exploitation attempts. System administrators should also consider implementing additional access controls and encryption layers for sensitive data, though the primary mitigation remains the application of the official security patches that correct the cryptographic algorithm selection process. The vulnerability demonstrates the critical importance of thorough validation in cryptographic implementations and serves as a reminder of how seemingly minor logic flaws can create significant security risks in system security frameworks.