CVE-2022-39898 is an improper access control vulnerability (CWE-284) identified in Samsung Mobile Devices, specifically affecting the IIccPhoneBook component on devices running Android versions Q (10), R (11), S (12), and T (13) prior to the December 2022 security maintenance release (SMR Dec-2022 Release 1). The vulnerability allows an attacker to access certain information stored on the USIM (Universal Subscriber Identity Module) without proper authorization. The IIccPhoneBook is responsible for managing phonebook entries stored on the SIM card, and improper access control here means that unauthorized applications or actors could potentially read sensitive data such as contacts or other USIM-stored information. Although no known exploits are currently reported in the wild, the vulnerability poses a risk of information disclosure. The lack of authentication or insufficient access control mechanisms in the affected component could allow local or potentially remote attackers with some level of access to the device to extract USIM data, which may include personal contact information or other subscriber-related data. Samsung has acknowledged the issue and addressed it in their December 2022 security update, but devices that have not applied this patch remain vulnerable. The vulnerability does not appear to allow modification or deletion of data, nor does it directly impact device availability or integrity, but the confidentiality of subscriber information is at risk.

For European organizations, the impact of this vulnerability primarily concerns the confidentiality of subscriber and contact information stored on Samsung mobile devices. Organizations that issue Samsung devices to employees, especially those handling sensitive or personal data, may face increased risks of data leakage if devices are compromised. This could lead to privacy violations under GDPR regulations, potential reputational damage, and exposure of sensitive contact networks. While the vulnerability does not directly enable device takeover or denial of service, the unauthorized access to USIM data could facilitate targeted phishing or social engineering attacks against employees or business contacts. Additionally, sectors with high security requirements such as government, finance, and critical infrastructure in Europe could be more sensitive to such data disclosures. The medium severity rating reflects the limited scope of impact (information disclosure only) and the requirement for local access or user-level compromise to exploit the vulnerability. However, given the widespread use of Samsung devices in Europe, the potential scale of exposure is significant if patches are not applied.

To mitigate this vulnerability, European organizations should prioritize the deployment of the Samsung December 2022 security maintenance release (SMR Dec-2022 Release 1) or later on all affected Samsung mobile devices. This patch addresses the improper access control in the IIccPhoneBook component. Organizations should implement mobile device management (MDM) solutions to enforce timely updates and monitor device compliance. Additionally, restricting installation of untrusted or third-party applications can reduce the risk of local exploitation. Employing endpoint security solutions that detect unusual access patterns to SIM data or phonebook information can provide early warning of exploitation attempts. User education on the risks of installing unknown apps and the importance of applying security updates is also critical. For highly sensitive environments, consider limiting the use of affected Samsung devices or isolating them from critical networks until patched. Regular audits of device security posture and access controls on mobile endpoints will further reduce risk.