CVE-2019-2084 in Android
Summary
by MITRE
In libxaac there is a possible out of bounds write due to a missing bounds check. This could lead to remote code execution with no additional execution privileges needed. User interaction is needed for exploitation. Product: AndroidVersions: Android-10Android ID: A-117494734
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Analysis
by VulDB Data Team • 09/11/2020
The vulnerability identified as CVE-2019-2084 resides within the libxaac library component of Android systems, specifically affecting Android 10 installations. This issue represents a critical security flaw that stems from an insufficient bounds checking mechanism within the audio decoding functionality. The vulnerability manifests as a potential out-of-bounds write condition that can be exploited to achieve remote code execution without requiring any special privileges or user permissions for initial access. The flaw exists in the way the library processes audio data, particularly when handling certain encoded audio streams that may contain malformed or maliciously constructed data patterns.
The technical nature of this vulnerability places it squarely within the category of buffer overflow conditions, specifically characterized by CWE-129 which describes improper validation of length of inputs. The absence of proper bounds checking in the libxaac library means that when processing audio data, the system fails to verify that incoming data fits within allocated memory boundaries before writing to memory locations. This missing validation creates a scenario where an attacker can craft specific audio content that, when processed by the vulnerable library, causes data to be written beyond the intended memory allocation, potentially overwriting adjacent memory regions including function pointers, return addresses, or other critical program data structures.
From an operational perspective, the exploitation of this vulnerability requires user interaction, meaning that an attacker must somehow convince a user to play or process a specially crafted audio file through the affected system. This interaction requirement typically involves social engineering tactics such as phishing emails containing malicious audio attachments, compromised websites delivering malicious content through web browsers, or other methods of user engagement. The fact that no additional execution privileges are required for exploitation makes this vulnerability particularly dangerous as it can be leveraged by attackers who have no prior access to the target system. The remote code execution capability means that successful exploitation could result in complete system compromise, allowing attackers to install malware, steal data, or establish persistent access to the affected device.
The impact of this vulnerability extends beyond individual device compromise to potentially affect large-scale deployments where Android devices are used in enterprise environments or critical infrastructure applications. The vulnerability's presence in libxaac, which is a core component of Android's audio processing pipeline, means that any application or service that utilizes audio playback functionality could potentially be exploited. This includes web browsers, media players, messaging applications, and other software components that handle audio content. The Android ID A-117494739 indicates that this vulnerability was properly tracked and addressed through Android's security update process, but the underlying issue demonstrates the ongoing challenges in securing multimedia processing libraries where complex decoding algorithms must handle diverse and potentially malicious input formats.
Mitigation strategies for CVE-2019-2084 primarily focus on applying the relevant Android security patches and updates that address the bounds checking deficiencies in the libxaac library. Organizations should ensure that all Android devices are updated to the latest security releases, particularly those containing fixes for the identified vulnerability. Network-based mitigations could include implementing content filtering systems that block or scan audio content before it reaches end-user devices, though this approach has limitations given the need for user interaction. The vulnerability also highlights the importance of secure coding practices and input validation in multimedia processing components, aligning with ATT&CK technique T1059.007 which covers the use of audio-based payloads for execution. Additionally, user education regarding the risks of downloading and playing audio content from untrusted sources remains a crucial defense mechanism, as the requirement for user interaction makes social engineering attacks a primary exploitation vector for this type of vulnerability.