CVE-2015-8891 in Android
Summary
by MITRE
Multiple integer overflows in app/aboot/aboot.c in the Qualcomm components in Android before 2016-07-05 on Nexus 5 and 7 (2013) devices allow attackers to bypass intended access restrictions via a crafted image, aka Android internal bug 28842418 and Qualcomm internal bug CR813930.
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Analysis
by VulDB Data Team • 09/01/2022
The vulnerability identified as CVE-2015-8891 represents a critical security flaw within the Qualcomm bootloader components of Android devices, specifically affecting Nexus 5 and Nexus 7 (2013) models. This issue resides in the app/aboot/aboot.c file which forms part of the Android bootloader implementation. The vulnerability stems from multiple integer overflow conditions that occur during image processing operations, creating a pathway for attackers to circumvent intended access controls. The flaw was particularly concerning as it affected devices running Android versions prior to the 2016-07-05 security update, leaving millions of devices exposed to potential exploitation.
The technical implementation of this vulnerability involves integer overflow conditions that occur when processing image files within the bootloader environment. These overflows happen during arithmetic operations where the result exceeds the maximum value that can be stored in the allocated integer variable, causing unexpected behavior in the system's memory management and access control mechanisms. When attackers craft malicious image files that trigger these overflows, the system's normal validation procedures are bypassed, allowing unauthorized access to restricted system components. The vulnerability operates at the bootloader level, which means it can potentially enable attackers to execute arbitrary code before the operating system fully loads, creating a persistent threat vector that operates below the normal security boundaries of the Android runtime environment.
The operational impact of CVE-2015-8891 extends beyond simple privilege escalation, as it enables attackers to bypass hardware-level security controls that are designed to protect the device's boot process and system integrity. This vulnerability creates a persistent backdoor that can be exploited to install malicious software, extract sensitive data, or modify critical system components before the device's normal security mechanisms are active. The flaw's location in the Qualcomm components means that it affects not just the Android operating system but also the underlying hardware security features that are integral to the device's trust model. Attackers can leverage this vulnerability to gain root access to devices, effectively neutralizing the security protections that are supposed to prevent unauthorized modifications to the system firmware and boot process.
Mitigation strategies for this vulnerability require immediate patching of affected Android devices with the security updates released by Google and Qualcomm. Organizations and individuals should ensure their Nexus 5 and Nexus 7 (2013) devices are updated to Android versions released after 2016-07-05 to address the integer overflow conditions. System administrators should implement device management policies that enforce automatic security updates and regularly monitor for vulnerabilities in embedded systems. The vulnerability aligns with CWE-190, Integer Overflow or Wraparound, which specifically addresses issues where integer arithmetic produces results that exceed the maximum value representable by the data type. From an ATT&CK framework perspective, this vulnerability maps to T1068, Exploitation for Privilege Escalation, and T1542, Pre-OS Boot, as it enables attackers to gain elevated privileges before the operating system initializes and provides traditional security controls. The remediation process should also include network monitoring to detect potential exploitation attempts and regular security assessments of embedded systems to identify similar vulnerabilities in other components of the device's security architecture.