Source: security@oppo.com
In /SM8250_Q_Master/android/vendor/oppo_charger/oppo/charger_ic/oppo_da9313.c, failure to check the parameter buf in the function proc_work_mode_write in proc_work_mode_write causes a vulnerability.
A critical vulnerability exists in the Oppo charger firmware, allowing for potential arbitrary code execution due to a missing parameter check in the proc_work_mode_write function. This flaw could lead to device compromise, allowing attackers to gain control of the device and potentially access sensitive data. Exploitation requires local access, but could be chained with other vulnerabilities for remote access.
Step 1: Access the Vulnerable Function: An attacker must first gain access to the device and interact with the /proc/ filesystem. This typically requires local access or a vulnerability that allows for arbitrary file system interaction.
Step 2: Craft a Malicious Payload: The attacker crafts a malicious input string (the payload) that is larger than the expected buffer size within proc_work_mode_write. This payload will overwrite adjacent memory regions.
Step 3: Write the Payload: The attacker writes the crafted payload to the /proc/ entry associated with proc_work_mode_write. This triggers the vulnerable function.
Step 4: Buffer Overflow: The proc_work_mode_write function attempts to write the oversized payload to the buffer without checking its size, causing a buffer overflow.
Step 5: Code Execution (Exploitation): Depending on the crafted payload, the overflow can overwrite critical data, such as function pointers or control flow data. This can lead to arbitrary code execution, allowing the attacker to execute malicious code within the context of the charger firmware.
The vulnerability stems from a missing bounds check on the buf parameter within the proc_work_mode_write function in oppo_da9313.c. This function is likely responsible for writing configuration data to the charger IC. Without proper validation of the input buffer size, an attacker can supply a crafted input that exceeds the allocated buffer, leading to a buffer overflow. This overflow can overwrite adjacent memory regions, potentially corrupting critical data structures or overwriting function pointers. Successful exploitation could allow an attacker to execute arbitrary code within the context of the charger firmware, leading to complete device compromise. The root cause is a lack of input validation, a common software security flaw.
Due to the nature of the vulnerability, it is unlikely to be directly targeted by sophisticated APTs. However, the vulnerability could be exploited by less skilled attackers or used in conjunction with other vulnerabilities. Not listed on CISA KEV.
Monitor file system access to /proc/ entries, specifically those related to charger functionality (e.g., proc_work_mode_write).
Analyze system logs for unusual activity related to the charger IC or power management.
Implement file integrity monitoring to detect changes to the oppo_da9313.c file or related binaries.
Inspect network traffic for unusual communication patterns originating from the device, which could indicate a compromised state.
Apply the vendor-provided patch to the charger firmware. This patch should include a bounds check on the buf parameter within the proc_work_mode_write function.
Implement input validation to ensure that the size of the input buffer is within acceptable limits before writing to the buffer.
Enable Address Space Layout Randomization (ASLR) and other memory protection mechanisms to make exploitation more difficult.
Regularly update the device's firmware to address security vulnerabilities.
Restrict access to the /proc/ filesystem where possible, limiting the attack surface.