CVE-2021-1047 in Android
Summary
by MITRE • 12/15/2021
In valid_ipc_dram_addr of cm_access_control.c, there is a possible out of bounds read due to an integer overflow. This could lead to local information disclosure with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-197966306References: N/A
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Analysis
by VulDB Data Team • 12/18/2021
The vulnerability identified as CVE-2021-1047 resides within the Android kernel's memory management subsystem, specifically in the valid_ipc_dram_addr function located in cm_access_control.c. This flaw represents a critical security weakness that demonstrates the dangers of improper integer handling in kernel-level code. The vulnerability manifests as a potential out-of-bounds read condition that can be exploited to gain unauthorized access to sensitive memory regions, making it particularly dangerous for mobile device security.
The technical root cause of this vulnerability stems from an integer overflow condition that occurs during address validation within the inter-process communication memory management system. When processing memory addresses for IPC operations, the system fails to properly validate integer values, allowing an attacker to manipulate input parameters that eventually lead to arithmetic overflow. This overflow results in a situation where memory access calculations produce values that exceed the legitimate bounds of allocated memory regions, creating opportunities for unauthorized data access. The vulnerability aligns with CWE-191, which specifically addresses integer underflow and overflow conditions, and represents a classic example of how improper integer arithmetic can lead to memory corruption vulnerabilities.
The operational impact of CVE-2021-1047 is significant as it enables local information disclosure attacks that require only system execution privileges for exploitation. This means that an attacker with local access to an Android device can potentially read sensitive memory contents that should remain protected, including potentially confidential data, system credentials, or other privileged information. The vulnerability's exploitation does not require user interaction, making it particularly concerning as it can be leveraged automatically by malicious processes running with system-level privileges. Attackers can use this weakness to extract information that could then be used for further exploitation or to understand system internals for more sophisticated attacks. The vulnerability's classification under the ATT&CK framework would likely fall under T1003 (Credential Dumping) or T1059 (Command and Scripting Interpreter) depending on the specific exploitation method employed.
Mitigation strategies for this vulnerability should focus on implementing proper integer overflow checks within the memory address validation logic. The recommended approach involves adding comprehensive bounds checking before any arithmetic operations that could potentially lead to overflow conditions, ensuring that all address calculations remain within legitimate memory boundaries. System administrators and device manufacturers should prioritize applying the latest security patches provided by Google and other vendors to address this specific vulnerability. Additionally, runtime protections such as stack canaries, address space layout randomization, and kernel address space layout randomization should be enabled to make exploitation more difficult. Regular security audits of kernel code should include specific reviews of integer arithmetic operations and memory management functions to identify similar vulnerabilities before they can be exploited in the wild. The fix should also consider implementing input sanitization and validation mechanisms to prevent malformed addresses from being processed by the vulnerable function, thereby reducing the attack surface and improving overall system security posture.