CVE-2021-25337
Samsung Mobile Devices Improper Access Control Vulnerability
Description
CVE-2021-25337 is an improper access control vulnerability in the clipboard service of Samsung mobile devices. This improper privilege management weakness allows untrusted applications to read or write certain local files on the device without proper authorization. The vulnerability affects Samsung Android devices running software prior to the SMR Mar-2021 Release 1. CVE-2021-25337 has been added to CISA's Known Exploited Vulnerabilities catalog due to confirmed active exploitation, highlighting the risk of data exposure and file manipulation on unpatched Samsung mobile devices.
KEV Information
CVSS Score
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:NOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| samsung | android | 9.0; 10.0; 11.0 |
Multiple CVSS Assessments
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
References
- https://security.samsungmobile.com(Vendor Advisory)
- https://security.samsungmobile.com/securityUpdate.smsb(Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-25337(US Government Resource)
Weakness Type
CWE-269: Improper Privilege Management
In CVE-2021-25337, the improper privilege management weakness manifests in Samsung's clipboard service, which fails to properly enforce access restrictions on local file operations. This allows untrusted applications to bypass intended security boundaries and gain unauthorized read/write access to files that should be protected by the system's privilege model.
Learn more: CWE-269 — Improper Privilege Management
Impact Analysis
CVE-2021-25337 carries a CVSS v3.1 score of 4.4 (Medium severity), reflecting a local access vulnerability with limited but concerning impact on Samsung mobile devices. Attack Vector (Local): Exploitation requires a malicious application to be installed on the target Samsung device, meaning the attacker must first convince the user to install an untrusted app through social engineering or a compromised app store. Attack Complexity (Low): Once a malicious application is installed, exploiting the clipboard service vulnerability is straightforward with no special conditions required. Privileges Required (None): The malicious application does not need elevated system privileges to exploit the vulnerability, as the flaw exists in how the clipboard service handles access control for standard applications. User Interaction (Required): Some user action is needed, such as installing the malicious application or interacting with the clipboard functionality. Confidentiality Impact (Low): Unauthorized read access to certain local files could expose sensitive user data. Integrity Impact (Low): The ability to write to local files could allow modification of device configuration or user data. The EPSS score of 0.48% (64th percentile) indicates a relatively low but non-negligible exploitation probability. However, the confirmed active exploitation in CISA's KEV catalog demonstrates that this vulnerability has been leveraged in targeted attacks against Samsung mobile device users.
Exploit Maturity
Active exploitation of CVE-2021-25337 has been confirmed by CISA, which added this Samsung clipboard service vulnerability to its Known Exploited Vulnerabilities catalog with a remediation deadline of November 29, 2022. The ransomware association is listed as Unknown, but the ability to read and write local files on a mobile device makes this vulnerability valuable for espionage and data theft operations targeting Samsung device users. The EPSS score of 0.48% (64th percentile) suggests limited widespread exploitation, but the KEV listing indicates that sophisticated threat actors have incorporated this vulnerability into targeted attack chains. No public proof-of-concept exploit code has been identified in the available references.
Remediation
- Update Samsung mobile devices immediately to the SMR Mar-2021 Release 1 or later as specified by Samsung's security bulletin. CISA requires federal agencies to apply mitigations by November 29, 2022, or discontinue use of the affected product. Check for updates via the Samsung security update page at security.samsungmobile.com.
- Enable automatic security updates on all Samsung mobile devices managed by your organization to ensure timely application of monthly Samsung Maintenance Releases (SMR) that address vulnerabilities like CVE-2021-25337.
- Implement mobile device management (MDM) policies to restrict installation of applications from untrusted sources, enforce application vetting, and monitor for potentially malicious applications that could exploit clipboard service vulnerabilities.
- Audit installed applications on affected Samsung devices for any unauthorized or suspicious applications that could be leveraging the clipboard service vulnerability. Review application permissions, particularly those requesting access to clipboard or file system operations.
- Enforce application sandboxing and runtime permissions through enterprise mobility management solutions, ensuring that applications cannot access files or services beyond their intended scope, and monitor for anomalous file access patterns on managed devices.
Technical Details
CVE-2021-25337 is rooted in an improper privilege management weakness (CWE-269) within the clipboard service component of Samsung's Android customization layer. The clipboard service fails to properly validate the calling application's privileges before granting access to local file read and write operations. With a Local Attack Vector and Low Attack Complexity, a malicious application installed on the device can leverage the clipboard service as a proxy to access files that would normally be restricted by Android's permission model. The vulnerability requires No Privileges from the attacking application beyond standard unprivileged app permissions, though User Interaction is Required to trigger the exploitation path. The clipboard service, which runs with elevated system privileges to facilitate inter-application data transfer, improperly exposes its file access capabilities to calling applications without adequate authorization checks, effectively creating a privilege escalation path through a trusted system service.
Frequently Asked Questions
Is CVE-2021-25337 being actively exploited?
Yes, CVE-2021-25337 is being actively exploited in the wild. CISA has confirmed active exploitation and added this vulnerability to the Known Exploited Vulnerabilities catalog with a remediation deadline of November 29, 2022. The vulnerability has been used in targeted attacks against Samsung mobile device users.
What products are affected by CVE-2021-25337?
CVE-2021-25337 affects Samsung mobile devices running Android software prior to the SMR Mar-2021 Release 1. This includes a broad range of Samsung Galaxy smartphones and tablets that had not yet received the March 2021 security maintenance release.
How do I fix CVE-2021-25337?
Update your Samsung mobile device to the SMR Mar-2021 Release 1 or later through the device's software update settings. Enable automatic security updates and implement MDM policies to restrict untrusted application installation. Check Samsung's security bulletin at security.samsungmobile.com for detailed update information.
How severe is CVE-2021-25337?
CVE-2021-25337 has a CVSS v3.1 score of 4.4 (Medium severity) with low impact on confidentiality and integrity. While the technical severity is moderate, the confirmed active exploitation by CISA and the widespread deployment of Samsung mobile devices elevate the practical risk, particularly for organizations managing Samsung device fleets.
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