CVE-2012-6422 in Android
Summary
by MITRE
The kernel in Samsung Galaxy S2, Galaxy Note 2, MEIZU MX, and possibly other Android devices, when running an Exynos 4210 or 4412 processor, uses weak permissions (0666) for /dev/exynos-mem, which allows attackers to read or write arbitrary physical memory and gain privileges via a crafted application, as demonstrated by ExynosAbuse.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 03/15/2019
The vulnerability identified as CVE-2012-6422 represents a critical kernel-level flaw affecting multiple Android devices that utilize Samsung Exynos 4210 or 4412 processors. This weakness stems from improper permission settings for the /dev/exynos-mem device file, which is a hardware memory management interface specific to Exynos SoC architectures. The device file is configured with overly permissive 0666 permissions, granting read, write, and execute access to all users and processes on the system. This configuration creates a fundamental security breach that directly violates the principle of least privilege and system integrity protection mechanisms that should normally restrict access to physical memory interfaces.
The technical exploitation of this vulnerability occurs through a crafted malicious application that leverages the weak permissions to directly access the /dev/exynos-mem device. This interface provides direct access to physical memory addresses, allowing attackers to read and write arbitrary memory locations without proper authorization. The attack vector specifically targets the Exynos memory management subsystem and demonstrates how improper device file permissions can create a backdoor for privilege escalation. This flaw enables attackers to bypass kernel security controls and potentially access sensitive system information, modify critical kernel data structures, or execute arbitrary code with kernel-level privileges. The vulnerability is classified under CWE-276, which deals with incorrect permissions for a resource, and represents a classic case of insufficient privilege checking in kernel space.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete system compromise and data exfiltration capabilities. Attackers with access to a malicious application can leverage this weakness to read kernel memory, access protected system information, modify critical system components, or even install persistent rootkits. The vulnerability affects a significant number of devices including Samsung Galaxy S2, Galaxy Note 2, and MEIZU MX models, representing a widespread security concern that affects millions of Android users. The attack demonstrates the dangerous potential of hardware-level interfaces when improperly secured, as it allows attackers to operate at the physical memory level rather than just the application level. This type of vulnerability is particularly concerning because it operates below the traditional application security model and can bypass most standard mobile security protections.
Mitigation strategies for this vulnerability require immediate system updates and kernel patches from device manufacturers, as the flaw exists at the hardware abstraction layer level. System administrators and device manufacturers should implement proper permission controls on the /dev/exynos-mem device file, restricting access to privileged system processes only. The solution involves changing the device file permissions from 0666 to more restrictive settings such as 0600 or 0640, ensuring that only root or designated kernel processes can access the memory management interface. Additionally, implementing kernel-level access controls and privilege separation mechanisms can prevent unauthorized applications from exploiting this interface. This vulnerability highlights the importance of secure hardware abstraction layer design and proper privilege management in mobile operating systems. Organizations should also consider implementing runtime monitoring to detect unauthorized access attempts to memory management interfaces and establish incident response procedures for potential exploitation of similar low-level vulnerabilities. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting kernel-level access and memory manipulation as part of the adversary's attack chain.