CVE-2020-0169 in Android
Summary
by MITRE
In RTTTL_Event of eas_rtttl.c, there is possible resource exhaustion due to a missing bounds check. This could lead to remote denial of service with no additional execution privileges needed. User interaction is needed for exploitation.Product: AndroidVersions: Android-10Android ID: A-123700383
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Analysis
by VulDB Data Team • 06/12/2020
The vulnerability identified as CVE-2020-0169 resides within the RTTTL_Event function in the eas_rtttl.c file, representing a critical resource exhaustion issue that affects Android 10 systems. This flaw manifests as a missing bounds check that allows malicious actors to exploit the system through remote means without requiring elevated privileges or additional execution capabilities. The vulnerability specifically targets the Real-Time Text Transfer Profile and Text Transfer Profile implementation within the Android multimedia framework, making it particularly concerning given the widespread use of these audio formats in mobile communications. The Android ID A-123700383 indicates this was properly tracked and documented within Google's security infrastructure, highlighting the severity of the issue.
The technical flaw stems from insufficient input validation within the RTTTL parsing mechanism, where the RTTTL_Event function fails to properly verify the boundaries of incoming data structures. This missing bounds check creates a condition where malformed RTTTL data can cause the system to allocate excessive memory resources or consume processing cycles without proper termination conditions. The vulnerability operates at the application layer, specifically within the audio processing components that handle ringtone and notification tone data. When an attacker crafts malicious RTTTL data and delivers it through a remote channel such as SMS or MMS messages, the vulnerable system processes this data without proper safeguards, leading to resource exhaustion. The lack of additional execution privileges required for exploitation makes this vulnerability particularly dangerous as it can be triggered through standard user interactions without requiring special attacker capabilities.
The operational impact of CVE-2020-0169 extends beyond simple denial of service conditions, as the resource exhaustion can potentially cause system instability and affect overall device performance. Mobile devices running Android 10 are susceptible to this vulnerability when processing incoming multimedia content, particularly when users receive notifications or messages containing malicious RTTTL data. The attack vector requires user interaction, typically through receiving a specially crafted message, but once triggered, the vulnerability can exhaust memory resources, CPU cycles, and other system resources. This can result in complete system hangs, application crashes, or forced reboots of affected devices, effectively rendering them temporarily unusable. The vulnerability aligns with CWE-129, which addresses insufficient bounds checking, and demonstrates characteristics consistent with attack patterns found in the MITRE ATT&CK framework under the technique of privilege escalation through resource exhaustion attacks.
Mitigation strategies for CVE-2020-0169 should focus on implementing proper bounds checking mechanisms within the RTTTL parsing functions and ensuring that all input data undergoes rigorous validation before processing. Android security updates and patches should enforce stricter validation of RTTTL data structures, implementing size limitations and boundary checks to prevent excessive resource allocation. System administrators should ensure that affected devices receive timely security updates, as Google has released patches addressing this specific vulnerability. Additionally, network-level monitoring should be implemented to detect and block suspicious RTTTL data patterns that may indicate exploitation attempts. Organizations should consider implementing application whitelisting policies that restrict processing of untrusted RTTTL content and maintain regular security assessments to identify potential vulnerabilities in multimedia processing components. The vulnerability serves as a reminder of the importance of input validation and bounds checking in preventing resource exhaustion attacks that can compromise system availability and user experience.