CVE-2022-20145 in Android
Summary
by MITRE • 06/15/2022
In startLegacyVpnPrivileged of Vpn.java, there is a possible way to retrieve VPN credentials due to a protocol downgrade attack. This could lead to remote escalation of privilege if a malicious Wi-Fi AP is used, with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-11Android ID: A-201660636
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Analysis
by VulDB Data Team • 06/15/2022
The vulnerability identified as CVE-2022-20145 resides within the Android operating system's VPN implementation, specifically in the startLegacyVpnPrivileged method located in the Vpn.java file. This flaw represents a critical security weakness that enables attackers to potentially extract VPN credentials through a protocol downgrade attack vector. The vulnerability affects Android 11 systems and is tracked under Android ID A-201660636, demonstrating the severity and widespread impact of this issue within the mobile platform ecosystem. The flaw exists in the privileged VPN management functionality, making it particularly dangerous as it operates at a system-level privilege context.
The technical implementation of this vulnerability stems from insufficient validation mechanisms during VPN protocol negotiation processes. When a device connects to a network, the system performs protocol validation to ensure secure communication channels are established. However, the startLegacyVpnPrivileged method fails to properly verify protocol integrity during connection establishment, creating opportunities for attackers to manipulate the protocol version negotiation. This protocol downgrade attack allows malicious actors to force the system into using weaker cryptographic protocols or authentication mechanisms, thereby exposing sensitive VPN credentials that would normally be protected. The vulnerability specifically targets the legacy VPN functionality that maintains backward compatibility with older protocol versions, which often contain known security weaknesses.
The operational impact of this vulnerability extends beyond simple credential theft, as it enables remote privilege escalation without requiring any additional execution privileges or user interaction. This means that an attacker positioned within range of a malicious Wi-Fi access point can exploit this vulnerability to gain unauthorized access to VPN credentials and potentially escalate their privileges on the target device. The attack does not require the user to perform any actions, as the exploitation occurs automatically during network connection establishment. This characteristic makes the vulnerability particularly dangerous in public Wi-Fi environments where users frequently connect to potentially malicious networks. The vulnerability's impact is amplified by the fact that it operates at the system level, potentially allowing attackers to access sensitive network resources and communications that should remain protected.
Security professionals should consider this vulnerability in relation to CWE-310, which addresses cryptographic issues and protocol weaknesses, and aligns with ATT&CK technique T1566 for social engineering through malicious Wi-Fi networks. Mitigation strategies should include immediate deployment of security patches provided by Google and device manufacturers, network administrators should implement additional monitoring for unusual protocol negotiation patterns, and users should avoid connecting to untrusted Wi-Fi networks. Organizations should also consider implementing network segmentation and additional authentication layers to reduce the potential impact of credential exposure. The vulnerability highlights the importance of proper protocol validation and secure cryptographic implementation in mobile operating systems, particularly when maintaining legacy compatibility that may introduce security risks.