CVE-2016-3835 in Android
Summary
by MITRE
The secure-session feature in the mm-video-v4l2 venc component in mediaserver in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before 2016-08-01 mishandles heap pointers, which allows attackers to obtain sensitive information via a crafted application, aka internal bug 28920116.
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Analysis
by VulDB Data Team • 09/12/2022
The vulnerability identified as CVE-2016-3835 resides within the mm-video-v4l2 venc component of Android's mediaserver process, specifically affecting Android versions 4.x prior to 4.4.4, 5.0.x prior to 5.0.2, 5.1.x prior to 5.1.1, and 6.x prior to the 2016-08-01 security update. This flaw manifests in the secure-session feature implementation where heap pointer management becomes corrupted, creating a potential information disclosure scenario. The vulnerability operates at the system level within the multimedia framework, specifically targeting the video encoder component that handles secure media processing operations.
The technical exploitation of this vulnerability stems from improper heap pointer handling within the mediaserver's video encoding subsystem. When a crafted application interacts with the secure-session feature, it can manipulate memory pointers in a way that allows unauthorized access to heap memory contents. This heap pointer mishandling creates a condition where sensitive information stored in memory locations adjacent to the manipulated pointers becomes accessible to the attacking application. The flaw represents a classic heap-based memory corruption vulnerability that falls under CWE-125: Uninitialized Memory Read, though it specifically manifests through pointer manipulation rather than direct memory access.
From an operational perspective, this vulnerability presents a significant risk to Android devices as it allows attackers to extract sensitive information from the system's memory space. The impact extends beyond simple information disclosure, as the leaked heap data may contain cryptographic keys, session tokens, or other confidential information that could be leveraged for further attacks. The vulnerability affects the core multimedia processing capabilities of the device, potentially compromising the security of media processing operations that rely on secure sessions. Attackers can exploit this without requiring elevated privileges, making it particularly dangerous as it can be triggered through ordinary applications.
The attack vector involves a malicious application that carefully constructs input parameters to the secure-session feature of the video encoder component. This approach aligns with ATT&CK technique T1068: Exploitation for Privilege Escalation and T1059: Command and Scripting Interpreter, as it leverages legitimate system interfaces to access restricted memory areas. The vulnerability's exploitation requires understanding of the underlying memory management structures and the specific pointer manipulation techniques that can cause heap corruption. Security researchers have classified this as a medium to high severity issue due to its potential for information disclosure and its ability to be triggered through legitimate application interfaces.
Mitigation strategies for CVE-2016-3835 primarily involve applying the security patches released by Google as part of their regular security updates. Organizations should ensure that all Android devices are updated to versions that contain the fix for this vulnerability, particularly focusing on the specific version ranges mentioned in the CVE description. System administrators should implement monitoring for unusual memory access patterns or application behavior that might indicate exploitation attempts. The vulnerability highlights the importance of proper memory management in system-level components and the need for comprehensive security testing of multimedia frameworks. Additionally, implementing application sandboxing and privilege separation can help reduce the potential impact if such vulnerabilities are exploited in the wild.