Source: security@oppo.com
In /SM8250_Q_Master/android/vendor/oppo_charger/oppo/oppo_vooc.c, the function proc_fastchg_fw_update_write in proc_fastchg_fw_update_write does not check the parameter len, resulting in a vulnerability.
A critical vulnerability exists in Oppo smartphone charging firmware, allowing for potential arbitrary code execution. This flaw, stemming from a missing length check in the proc_fastchg_fw_update_write function, could enable attackers to overwrite critical memory regions and compromise the device. Exploitation could lead to device compromise, data theft, and denial-of-service.
Step 1: Trigger Condition: The attacker identifies an Oppo device with the vulnerable firmware version.
Step 2: Payload Preparation: The attacker crafts a malicious firmware update file, designed to exploit the buffer overflow. This file contains a payload that will overwrite critical memory areas.
Step 3: Firmware Update Initiation: The attacker initiates the firmware update process, likely through a custom application or by exploiting another vulnerability that allows for firmware update control.
Step 4: Data Transmission: The attacker's malicious firmware update file is sent to the device, triggering the vulnerable proc_fastchg_fw_update_write function.
Step 5: Buffer Overflow: The proc_fastchg_fw_update_write function, lacking a length check, writes the attacker-controlled data beyond the bounds of the allocated buffer.
Step 6: Memory Corruption: The overflow overwrites adjacent memory regions, potentially including code execution pointers, system data, or other sensitive information.
Step 7: Code Execution (Exploitation): If successful, the attacker's payload gains control of the device, executing arbitrary code, leading to device compromise, data theft, or a denial-of-service condition.
The vulnerability lies within the proc_fastchg_fw_update_write function in oppo_vooc.c. This function, responsible for handling firmware updates for Oppo's fast-charging technology, fails to properly validate the len parameter, which specifies the size of the data being written. This lack of bounds checking allows for a buffer overflow. An attacker can craft a malicious firmware update with a size exceeding the allocated buffer, leading to the overwriting of adjacent memory regions. This could include critical system data, code execution, or control of the device. The root cause is a missing if statement or similar check to validate the len parameter against the size of the destination buffer. This allows for an out-of-bounds write, a classic memory corruption vulnerability.
While no specific APT groups are known to be actively exploiting this vulnerability, the potential for remote code execution makes it attractive to various threat actors. This vulnerability is not listed on the CISA KEV (Known Exploited Vulnerabilities) list, but the potential for exploitation warrants close monitoring.
Monitor device logs for unusual firmware update attempts or failures.
Analyze network traffic for suspicious communication patterns related to firmware updates.
Implement file integrity monitoring to detect unauthorized modifications to system files.
Examine device memory dumps for signs of buffer overflows or memory corruption.
Use static analysis tools to identify vulnerable code patterns in firmware images.
Apply the vendor-provided security patch or firmware update as soon as it becomes available.
Implement input validation to ensure that the len parameter in proc_fastchg_fw_update_write is within acceptable bounds.
Employ memory protection mechanisms, such as address space layout randomization (ASLR) and data execution prevention (DEP), to mitigate the impact of a successful exploit.
Regularly audit the codebase for similar vulnerabilities, focusing on functions that handle user-supplied data.
Implement a robust firmware update process that includes cryptographic verification of firmware images to prevent the installation of malicious updates.