CVE-2014-9873 in Android
Summary
by MITRE
Integer underflow in drivers/char/diag/diag_dci.c in the Qualcomm components in Android before 2016-08-05 on Nexus 5 and 7 (2013) devices allows attackers to gain privileges or obtain sensitive information via a crafted application, aka Android internal bug 28750726 and Qualcomm internal bug CR556860.
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Analysis
by VulDB Data Team • 09/12/2022
The vulnerability identified as CVE-2014-9873 represents a critical integer underflow condition within the diagnostic communication interface driver component of Android operating systems. This flaw exists in the drivers/char/diag/diag_dci.c file within Qualcomm's proprietary Android components, specifically affecting Nexus 5 and Nexus 7 (2013) devices released before the security patch date of August 5, 2016. The vulnerability stems from improper input validation and arithmetic handling within the diagnostic communication interface that governs how applications interact with the device's diagnostic subsystem.
The technical implementation of this vulnerability involves an integer underflow condition that occurs when processing diagnostic communication interface commands. When a crafted application submits malicious input parameters to the diagnostic driver, the system fails to properly validate the integer values before performing arithmetic operations. This allows attackers to manipulate the integer variables in such a way that they wrap around to extremely large positive values when subtracting or performing other mathematical operations on negative values. The underlying CWE classification for this issue is CWE-191, which specifically addresses integer underflows where a signed integer is subtracted from zero or another value, resulting in an underflow condition that produces an unexpectedly large positive value.
The operational impact of this vulnerability extends beyond simple privilege escalation to include potential information disclosure and system compromise. Attackers can exploit this condition to execute arbitrary code with elevated privileges, potentially gaining root access to the device and full control over the Android operating system. The diagnostic communication interface typically operates with high privileges and provides access to low-level device functions, making this a particularly dangerous vulnerability for mobile devices. Additionally, the vulnerability allows for sensitive information extraction from the device's memory and system components, potentially exposing cryptographic keys, user credentials, and other confidential data.
The exploitation of this vulnerability aligns with several tactics described in the MITRE ATT&CK framework, particularly those related to privilege escalation and credential access. The attack vector involves application-level exploitation through malicious applications that leverage the underlying integer underflow to bypass security controls. This vulnerability demonstrates the critical importance of input validation in kernel-level drivers and highlights the risks associated with proprietary code components that may lack proper security testing. The Android internal bug identifier 28750726 and Qualcomm internal bug CR556860 indicate that this issue was recognized by both vendors but required coordinated patching across multiple software layers. Organizations should implement immediate security patches and monitor for exploitation attempts, while also considering the broader implications of similar vulnerabilities in other mobile device drivers and embedded systems components.
The remediation approach for this vulnerability requires comprehensive system updates including the latest Android security patches and Qualcomm firmware updates. Device administrators should ensure that all affected Nexus devices receive the appropriate security updates, and organizations should implement robust patch management processes to prevent similar issues from occurring in other embedded systems. The vulnerability also underscores the need for enhanced security testing of kernel modules and driver components, particularly those handling privileged operations and interfacing with hardware diagnostic subsystems.