CVE-2015-6614 in Android
Summary
by MITRE
Telephony in Android 5.x before 5.1.1 LMY48X allows attackers to gain privileges, and consequently bypass intended network-interface restrictions, perform expensive data transfers, or cause a denial of service (call-reception outage or mute manipulation), via a crafted application, aka internal bug 21900139.
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Analysis
by VulDB Data Team • 06/26/2022
The vulnerability identified as CVE-2015-6614 represents a critical privilege escalation flaw within the Android telephony subsystem affecting versions 5.x before 5.1.1 LMY48X. This issue resides in the underlying telephony framework that manages call processing and network interface controls, creating a pathway for malicious applications to bypass security restrictions that are typically enforced by the operating system. The vulnerability stems from improper validation of telephony service requests, allowing crafted applications to manipulate the system's telephony interfaces without proper authorization. The flaw specifically impacts the call reception functionality and audio processing mechanisms within the Android operating system, potentially enabling attackers to execute unauthorized operations that should be restricted to system-level components. This vulnerability directly violates the principle of least privilege by permitting applications to elevate their capabilities beyond normal operational boundaries.
The technical implementation of this vulnerability exploits weaknesses in the telephony service binder interface where applications can manipulate the system's call handling mechanisms. Attackers can craft malicious applications that leverage the system's telephony services to gain elevated privileges, effectively bypassing the intended network interface restrictions that normally prevent applications from accessing or modifying core telephony functions. The flaw enables unauthorized access to the system's audio processing components, allowing manipulation of call reception behavior including causing call reception outages, audio muting, or performing expensive data transfers through the telephony interface. This exploitation mechanism operates through the Android framework's inter-process communication system where telephony service requests are processed, creating a potential attack surface that allows privilege escalation from regular application context to system-level privileges. The vulnerability's impact extends beyond simple privilege elevation as it can be leveraged to disrupt normal telephony operations and potentially perform unauthorized data transfers through the network interface.
The operational impact of CVE-2015-6614 creates significant security implications for Android devices running affected versions, as it provides attackers with the capability to manipulate core telephony functions without proper authentication or authorization. The vulnerability can be exploited to cause service disruption through call reception outages, effectively rendering the device unable to receive calls during the attack period. Additionally, the ability to manipulate audio settings allows for mute manipulation that can be used for surveillance or communication disruption purposes. The potential for expensive data transfers through the telephony interface presents a risk of resource exhaustion and unauthorized data consumption, while the privilege escalation capability enables further exploitation of other system components. This vulnerability aligns with CWE-264, which addresses permissions, privileges, and access controls, specifically targeting the improper handling of system-level privileges within the telephony framework. The attack vector can be classified under ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation," demonstrating how a vulnerability in system services can be leveraged to gain elevated system access.
Mitigation strategies for this vulnerability require immediate system updates to Android 5.1.1 LMY48X or later versions where the issue has been patched by Google. Organizations should implement application whitelisting policies to prevent installation of untrusted applications that could exploit this vulnerability, while monitoring telephony service usage for abnormal patterns that might indicate exploitation attempts. Network administrators should consider implementing additional security controls at the network level to detect and prevent unauthorized data transfers through telephony interfaces. Device manufacturers and carriers should ensure timely deployment of security patches and maintain awareness of similar vulnerabilities within the Android telephony framework. The vulnerability highlights the importance of proper input validation and privilege checking within system services, particularly those that interface with critical hardware components such as telephony hardware. Security teams should also implement monitoring solutions that can detect abnormal call processing behavior or unauthorized access attempts to telephony services, providing early warning capabilities for potential exploitation attempts.