This long read post will discuss a critical vulnerability (CVE-2023-21130) found in Android 13's Bluetooth stack. This vulnerability can lead to remote code execution (RCE) on affected devices with no additional execution privileges required and no user interaction needed for exploitation.
We will provide a detailed description of the vulnerability, its root cause, and a code snippet illustrating the problematic code. Furthermore, we will provide links to the original references and resources for further research.
Description
A buffer overflow vulnerability exists in the btm_ble_periodic_adv_sync_lost function of the btm_ble_gap.cc source file, which is a part of the Android 13 Bluetooth software stack.
Exploit Details
Successful exploitation of this vulnerability allows a remote attacker to execute arbitrary code on the affected devices. The attacker only needs to send a specifically crafted Bluetooth advertisement or create a periodic advertising train during the synchronization process to trigger the buffer overflow. This can lead to Remote Code Execution (RCE) with no additional execution privileges needed and no user interaction is needed for exploitation.
The Root Cause
The root cause of this vulnerability is the lack of proper validation of the adv_report.len parameter when processing periodic advertising reports in the btm_ble_periodic_adv_sync_lost function.
A threat actor can send a specially crafted Bluetooth advertisement that causes a buffer overflow, ultimately leading to RCE.
// btm_ble_gap.cc
void btm_ble_periodic_adv_sync_lost(const tBLE_PERIODIC_ADV_SYNC_LOST* p_data) {
adv_data_len = p_data->adv_report.len;
// ...
// Buffer overflow vulnerability here
memcpy(p_buf, p_data->adv_report.p_data, adv_data_len);
// ...
}
In this code snippet, the memcpy function is called to copy the adv_data_len bytes from adv_report.p_data to p_buf without verifying the length. This lack of validation can lead to a buffer overflow when an attacker sends a specially crafted advertisement with an excessively large length value. This can result in the attacker gaining control over the execution flow and achieving RCE.
Original References
1. Android Security Bulletin link
2. Google's Issue Tracker link
3. CVE Details link
Mitigation and Patches
Google has released patches to fix this vulnerability, which are included in the latest Android Security Patch Level. Device manufacturers and users are urged to apply the latest security update as soon as possible to avoid potential exploitation.
Conclusion
In this post, we have discussed CVE-2023-21130, a critical Remote Code Execution vulnerability discovered in Android 13's Bluetooth stack. The vulnerability results from a buffer overflow in the btm_ble_periodic_adv_sync_lost function of the btm_ble_gap.cc source file.
Practitioners should be aware of the risks associated with this vulnerability and apply the security patches provided by Google to mitigate the threat. Exploitation of this vulnerability can lead to severe consequences for affected devices and users.
Timeline
Published on: 06/15/2023 19:15:00 UTC
Last modified on: 06/22/2023 13:39:00 UTC