CVE-2019-9457 in Android
Summary
by MITRE
In the Android kernel in ELF file loading there is possible memory corruption due to an integer overflow. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 12/13/2023
The vulnerability identified as CVE-2019-9457 resides within the Android kernel's implementation of ELF file loading mechanisms, representing a critical security flaw that undermines system integrity. This issue manifests as an integer overflow condition that occurs during the processing of executable files, specifically when the kernel attempts to calculate memory allocation sizes for loaded ELF binaries. The flaw exists in the kernel's handling of file size parameters during the dynamic allocation process, where an improperly validated integer value can exceed its maximum representable range, leading to unexpected behavior in memory management operations.
The technical exploitation of this vulnerability leverages the integer overflow condition to manipulate memory allocation calculations, resulting in memory corruption that can be leveraged for privilege escalation. When an attacker crafts a malicious ELF file with manipulated header values, the kernel's ELF loader performs arithmetic operations that overflow the integer boundaries, causing subsequent memory allocation to occur at incorrect offsets or sizes. This memory corruption can overwrite critical kernel data structures or memory regions that control privilege levels, effectively allowing a malicious process to elevate its privileges from regular user level to kernel level without requiring any additional execution privileges or user interaction.
The operational impact of CVE-2019-9457 is particularly severe as it enables local privilege escalation with no user interaction requirements, making it highly dangerous in environments where untrusted users or applications might have access to the system. The vulnerability affects Android devices running kernel versions prior to the patch release, with exploitation occurring at the kernel level where the attacker gains complete control over system operations. This flaw aligns with CWE-190, which specifically addresses integer overflow conditions, and represents a classic example of how improper input validation can lead to memory corruption vulnerabilities. The attack vector operates entirely within the kernel space, making it particularly challenging to detect and mitigate through traditional application-level security measures.
The exploitation of this vulnerability follows ATT&CK technique T1068, which covers 'Local Privilege Escalation' through kernel exploits, and specifically aligns with the use of kernel memory corruption as a method for privilege elevation. Security researchers have documented that the vulnerability can be reliably exploited on Android devices with affected kernel versions, where the integer overflow in ELF loading creates a predictable memory corruption pattern that allows for privilege escalation attacks. The lack of user interaction requirements makes this vulnerability particularly dangerous as it can be exploited silently in the background without any user awareness, potentially allowing attackers to gain persistent access to devices and execute arbitrary code with kernel-level privileges. Mitigation strategies include applying the latest kernel security patches from Android vendors, implementing kernel address space layout randomization, and deploying kernel module integrity checking mechanisms to prevent exploitation of such memory corruption vulnerabilities.