CVE-2018-5820 in Android
Summary
by MITRE
In Qualcomm Android for MSM, Firefox OS for MSM, and QRD Android with all Android releases from CAF using the Linux kernel before security patch level 2018-04-05, in the function wma_tbttoffset_update_event_handler(), a parameter received from firmware is used to allocate memory for a local buffer and is not properly validated. This can potentially result in an integer overflow subsequently leading to a heap overwrite.
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Analysis
by VulDB Data Team • 01/21/2020
The vulnerability identified as CVE-2018-5820 affects Qualcomm Android platforms, Firefox OS for MSM, and QRD Android systems utilizing Linux kernel versions prior to the 2018-04-05 security patch level. This issue resides within the wireless media access layer implementation where firmware communicates with the kernel driver through the wma_tbttoffset_update_event_handler function. The flaw represents a critical memory safety issue that can be exploited to compromise system integrity and potentially execute arbitrary code.
The technical root cause involves improper validation of parameters received from firmware within the wma_tbttoffset_update_event_handler function. When firmware sends data to the kernel driver, this data is used to determine the size of a local buffer allocation. The vulnerability manifests as an integer overflow condition that occurs during the parameter validation process, where the input value is not adequately checked before being used in memory allocation calculations. This allows an attacker to manipulate the buffer size parameter to exceed the maximum allowable value for integer arithmetic, resulting in an integer overflow that subsequently causes a heap overwrite condition.
The operational impact of this vulnerability is severe as it enables attackers to potentially execute arbitrary code with kernel-level privileges. The heap overwrite condition can be leveraged to corrupt memory structures, manipulate kernel data, or redirect execution flow to malicious code. This represents a privilege escalation vulnerability that can be exploited from unprivileged user contexts to gain kernel-level access, making it particularly dangerous in mobile environments where system integrity is paramount. The vulnerability affects all Android releases from the Common Android Framework (CAF) that utilize the Linux kernel, spanning multiple generations of Qualcomm-based mobile devices.
The vulnerability aligns with CWE-190, which identifies integer overflow and underflow conditions, and demonstrates characteristics consistent with the ATT&CK technique T1068, which involves exploiting legitimate credentials or privileges to execute malicious code. The memory corruption resulting from the heap overwrite can be exploited through various attack vectors including firmware manipulation, wireless packet injection, or through compromised applications that can trigger the vulnerable code path. Organizations should implement immediate mitigation strategies including applying the relevant security patches from Qualcomm and Android, disabling unnecessary wireless functionality, and monitoring for suspicious memory allocation patterns in kernel modules. The vulnerability underscores the critical importance of proper input validation in kernel-level code and highlights the need for robust memory management practices in embedded systems and mobile platforms.