CVE-2018-9461 in Android
Summary
by MITRE • 01/18/2025
In onAttachFragment of ShareIntentActivity.java, there is a possible way for an app to read files in the messages app due to a race condition. 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 • 02/19/2025
The vulnerability identified as CVE-2018-9461 resides within the ShareIntentActivity.java component of an Android application, specifically manifesting in the onAttachFragment method where a race condition exists that allows for unintended file access. This flaw represents a critical security weakness that enables malicious applications to potentially read sensitive data from the messages application, creating a significant vector for privilege escalation attacks. The vulnerability stems from improper synchronization mechanisms during fragment attachment processes, where concurrent access to shared resources occurs without adequate protective measures.
The technical implementation of this vulnerability involves a race condition scenario where multiple threads or processes attempt to access the same file system resources simultaneously during the fragment attachment lifecycle. When an application attaches a fragment through the onAttachFragment method, the system fails to properly synchronize access to underlying message storage components, allowing an attacker to exploit this timing window to read files that should normally be restricted to the legitimate messaging application. This race condition creates a window of opportunity where unauthorized access can occur without requiring any user interaction or additional privileges beyond what the malicious application already possesses.
The operational impact of CVE-2018-9461 extends beyond simple data theft, as it enables local privilege escalation that can potentially allow attackers to gain elevated system privileges. An attacker with a malicious application installed on the device can leverage this vulnerability to access sensitive message data, including SMS and MMS content, personal communications, and potentially other confidential information stored within the messaging application's protected data stores. The absence of user interaction requirements makes this vulnerability particularly dangerous as it can be exploited automatically without any user awareness or consent, representing a significant threat to device security and user privacy.
Security professionals should consider this vulnerability in the context of CWE-362, which specifically addresses race conditions in software implementations, and its alignment with ATT&CK technique T1068, which covers local privilege escalation through system weaknesses. The vulnerability demonstrates how improper resource management and synchronization can create persistent security flaws that remain exploitable across multiple system versions and configurations. Organizations should implement immediate mitigations including code reviews to address synchronization issues in fragment management, application sandboxing measures, and regular security assessments to identify similar race condition vulnerabilities in other system components.
The remediation approach requires developers to implement proper synchronization mechanisms within the onAttachFragment method and other fragment lifecycle methods to prevent concurrent access to shared resources. This includes utilizing appropriate locking mechanisms, implementing proper resource management protocols, and conducting thorough testing of concurrent access scenarios. Additionally, Android application developers should adopt defensive programming practices that minimize the attack surface for such vulnerabilities, including restricting file system access permissions and implementing proper input validation to prevent exploitation of similar race condition scenarios in other application components.