CVE-2023-21240 in Android
Summary
by MITRE • 07/13/2023
In Policy of Policy.java, there is a possible boot loop due to resource exhaustion. This could lead to local denial of service with no additional execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 07/13/2023
The vulnerability identified as CVE-2023-21240 represents a critical resource exhaustion issue within the policy management component of a software system, specifically within the Policy.java file. This flaw manifests as a potential boot loop condition that can result in local denial of service attacks. The vulnerability is particularly concerning because it requires no additional execution privileges for exploitation, making it accessible to any local user with basic system access. The absence of user interaction requirements means that the attack can be initiated automatically without any deliberate action from the victim, significantly increasing its threat surface and potential impact. This type of vulnerability typically affects systems where policy enforcement mechanisms are critical to system operation and where resource management is not properly implemented to handle malicious or excessive resource consumption patterns.
The technical flaw stems from inadequate resource management within the policy evaluation process, where the system fails to properly monitor or limit resource consumption during policy processing. When the policy engine encounters certain conditions or malformed policy configurations, it can enter a state where it continuously consumes system resources without proper bounds or termination conditions. This resource exhaustion can manifest as excessive memory allocation, CPU cycles, or file descriptor usage, ultimately leading to the system becoming unresponsive or entering a boot loop where it continuously attempts to restart but fails due to resource constraints. The vulnerability falls under CWE-400, which specifically addresses "Uncontrolled Resource Consumption" and is classified as a denial of service condition. The root cause is typically related to insufficient input validation and resource limiting mechanisms within the policy processing framework, where the system does not properly handle edge cases or malicious inputs that could trigger unlimited resource consumption.
The operational impact of CVE-2023-21240 extends beyond simple system unavailability as it can compromise the stability and reliability of entire infrastructure components that depend on policy enforcement. Local denial of service attacks can disrupt critical system services, prevent legitimate users from accessing resources, and potentially cause cascading failures in dependent systems. The vulnerability affects systems where policy enforcement is fundamental to operations, such as network security appliances, identity management systems, or any platform that relies heavily on policy-based access controls. In enterprise environments, this could lead to significant operational disruptions, requiring system administrators to perform emergency restarts or manual intervention to restore service. The attack vector is particularly dangerous because it can be exploited silently without detection, as no user interaction is required, potentially allowing an attacker to maintain persistent denial of service conditions over extended periods.
Mitigation strategies for CVE-2023-21240 should focus on implementing comprehensive resource monitoring and limiting mechanisms within the policy processing framework. System administrators should deploy proper resource quotas and limits on policy evaluation processes to prevent unlimited consumption of system resources. The implementation of input validation and sanitization measures can help prevent malformed policy configurations from triggering the resource exhaustion condition. Additionally, regular system monitoring should be implemented to detect unusual resource consumption patterns that could indicate exploitation attempts. The solution approach aligns with ATT&CK technique T1499.004, which covers "Utilities: System Shutdown/Reboot," as the vulnerability essentially causes system instability that mimics shutdown/reboot conditions. Organizations should also consider implementing automated alerting systems that can detect and respond to resource exhaustion events before they escalate to full denial of service conditions. Regular security updates and patches should be applied promptly to address the underlying resource management flaws in the policy processing engine, while also conducting thorough code reviews to identify similar vulnerabilities in other system components that might be susceptible to the same class of resource exhaustion attacks.