CVE-2018-21087 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with L(5.x), M(6.x), and N(7.x) software. There is a vnswap heap-based buffer overflow via the store function, with resultant privilege escalation. The Samsung ID is SVE-2017-10599 (January 2018).
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Analysis
by VulDB Data Team • 10/09/2020
The vulnerability CVE-2018-21087 represents a critical heap-based buffer overflow flaw affecting Samsung mobile devices running on Android Lollipop (5.x), Marshmallow (6.x), and Nougat (7.x) operating system versions. This vulnerability specifically resides within the vnswap component of the Samsung mobile operating system, which handles virtual memory management operations. The issue manifests through the store function implementation, where insufficient input validation allows malicious actors to manipulate memory allocation processes. The vulnerability was assigned the Samsung internal identifier SVE-2017-10599 and was publicly disclosed in January 2018, highlighting a significant security gap in mobile device memory management systems. The flaw demonstrates characteristics consistent with CWE-122, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to write beyond allocated memory regions. This vulnerability directly relates to the broader category of memory corruption flaws that have historically enabled privilege escalation attacks in mobile operating systems.
The technical exploitation of this vulnerability occurs when the vnswap store function processes user-supplied data without proper boundary checks, leading to a heap-based buffer overflow condition. When malicious input exceeds the allocated buffer size, it overwrites adjacent memory locations within the heap, potentially corrupting critical data structures or executable code. This memory corruption can be leveraged to execute arbitrary code with elevated privileges, as the overflow may overwrite function pointers, return addresses, or other critical control data within the memory layout. The vulnerability's exploitation requires careful crafting of input data to precisely overwrite the necessary memory locations while maintaining program execution flow. Attackers can utilize this flaw to gain root access to the device, effectively bypassing the normal security boundaries of the Android operating system. The heap overflow nature of this vulnerability makes it particularly dangerous as it can be exploited to manipulate the memory layout in ways that are difficult to detect and prevent through standard security mechanisms.
The operational impact of CVE-2018-21087 extends beyond simple privilege escalation, as it provides attackers with complete control over affected Samsung devices. Once successfully exploited, adversaries can access all device data, install malicious applications, modify system configurations, and potentially use the compromised device as a pivot point for further attacks within network environments. The vulnerability affects millions of devices running the specified Android versions, creating a substantial attack surface for threat actors. The privilege escalation capability means that attackers can bypass Android's security model, including application sandboxing and user permission controls. From an ATT&CK framework perspective, this vulnerability maps to techniques such as T1068 (Exploitation for Privilege Escalation) and T1059 (Command and Scripting Interpreter), enabling attackers to establish persistent access and execute malicious payloads. The vulnerability's presence in multiple Android versions suggests a systemic issue in Samsung's memory management implementation that required urgent patching across affected device models.
Mitigation strategies for CVE-2018-21087 primarily involve applying the relevant security patches released by Samsung and Google as part of their regular security updates. Users should ensure their devices receive and install all available security updates immediately upon release, as these patches typically address the underlying buffer overflow conditions through improved input validation and memory management. Device manufacturers should implement additional security measures such as heap randomization, stack canaries, and address space layout randomization to make exploitation more difficult. Organizations managing Samsung devices should conduct regular vulnerability assessments to identify and remediate affected systems, particularly in enterprise environments where device security is paramount. The vulnerability highlights the importance of proactive security measures and regular patch management, as it demonstrates how memory corruption flaws can be systematically exploited to achieve complete device compromise. Security teams should also consider implementing monitoring solutions that can detect anomalous behavior patterns consistent with heap overflow exploitation attempts, providing additional defense-in-depth measures against similar vulnerabilities.