CVE-2021-39652 in Android
Summary
by MITRE • 12/15/2021
In sec_ts_parsing_cmds of (TBD), there is a possible out of bounds write due to an incorrect bounds check. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-194499021References: N/A
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Analysis
by VulDB Data Team • 12/18/2021
The vulnerability identified as CVE-2021-39652 represents a critical out-of-bounds write flaw within the sec_ts_parsing_cmds function of the Android kernel. This issue resides in the timestamp parsing commands component that handles time-related data processing. The vulnerability stems from an improper bounds check implementation that fails to adequately validate array indices or buffer limits during data processing operations. Such a flaw in kernel-level code processing timestamp information creates a significant security risk that could be exploited to gain elevated privileges within the system.
The technical nature of this vulnerability places it squarely within the CWE-787 category of out-of-bounds write conditions, which is classified as a direct consequence of inadequate input validation and memory management controls. The flaw specifically affects the Android kernel's handling of timestamp data parsing commands, where the bounds checking mechanism is insufficient to prevent buffer overflows. This vulnerability operates at the kernel level, requiring system execution privileges for exploitation but not user interaction, making it particularly dangerous as it can be leveraged by malicious processes already running with system-level access.
The operational impact of this vulnerability extends beyond simple privilege escalation to potentially enable complete system compromise. An attacker with local system privileges could exploit this flaw to execute arbitrary code with the highest privilege level available to the kernel, effectively gaining root access to the Android device. The implications are particularly severe given that this vulnerability affects the core kernel functionality and could be exploited to modify critical system components, install malicious software, or disable security features. The lack of user interaction requirement means that exploitation could occur automatically when timestamp data is processed, potentially leading to stealthy and persistent attacks.
Mitigation strategies for CVE-2021-39652 should focus on immediate kernel updates from Android vendors, as the primary fix involves correcting the bounds checking implementation within the sec_ts_parsing_cmds function. Organizations should implement comprehensive monitoring for unusual timestamp processing activities and establish robust patch management protocols to ensure timely deployment of security updates. The vulnerability aligns with ATT&CK technique T1068 which covers "Exploitation for Privilege Escalation" and could potentially map to T1543 which deals with "Create or Modify System Process" as exploitation may involve creating malicious system processes. Additionally, defensive measures should include kernel memory protection mechanisms and enhanced input validation controls to prevent similar issues from arising in other kernel components.