Samsung Mobile Devices Clipboard Service Privilege Escalation and Arbitrary File Read/Write Vulnerability (CVE-2021-25337) Analysis & Mitigation Guide
Executive & SecOps Summary
SECOPS ASSESSMENTSamsung mobile devices running software versions prior to SMR (Samsung Security Maintenance Release) Mar-2021 Release 1
Untrusted local applications can bypass sandbox boundaries to read or write sensitive local files, potentially leading to data theft or privilege escalation
Immediately apply the official Samsung security update (SMR Mar-2021 Release 1 or later)
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
Users must immediately perform an Over-The-Air (OTA) software update via the device settings. For enterprise environments, verify the patch level using MDM or ADB commands.
# Verify the current Android Security Patch Level via ADB
adb shell getprop ro.build.version.security_patch
# Ensure the output date is '2021-03-01' or later.2. Temporary Workaround & Hardening Configuration
If immediate patching is not feasible, restrict the installation of untrusted third-party applications and disable USB debugging to minimize local attack vectors.
# Disable installation of apps from unknown sources
adb shell settings put secure install_non_market_apps 0
# Disable ADB debugging to prevent local exploitation vectors
adb shell settings put global adb_enabled 03. Log Audit & IoC Verification Commands
Audit the device logs (Logcat) to detect anomalous Binder transactions or unauthorized file access attempts related to the clipboard service.
# Filter Logcat for suspicious clipboard service activities and access violations
adb logcat -d | grep -Ei 'clipboard|semclipboard|access denied'Block Kernel Privilege Escalation & Ransomware Payloads Before You Can Reboot
Protect unpatched Windows, Linux, and macOS workloads against in-memory exploitation and lateral movement with autonomous EDR.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability (CVE-2021-25337) is caused by improper access control (CWE-269) within the Clipboard Service of Samsung mobile devices. The clipboard component, which runs with elevated system privileges, fails to properly validate caller permissions and sanitize file paths when handling requests from external applications, allowing unauthorized local apps to access restricted system files.
2. Exploitation Mechanics & Attack Scenario
An attacker exploits this vulnerability by deploying a malicious, low-privilege application on the target device. The malicious app invokes the vulnerable interface of the Samsung Clipboard Service via Android's Binder IPC mechanism. By passing manipulated file path parameters, the attacker leverages the elevated privileges of the clipboard service to read from or write to arbitrary files outside the application's sandbox.
3. Infrastructure & Business Impact
This vulnerability is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, indicating active exploitation in the wild. In an enterprise environment, compromise of an employee's mobile device via this vulnerability can lead to the exposure of confidential corporate data, session tokens, and personal information, as well as potential device takeover through secondary privilege escalation.
Official Vendor Advisories & References
Improper access control in clipboard service in Samsung mobile devices prior to SMR Mar-2021 Release 1 allows untrusted applications to read or write certain local files.
Frequently Asked SecOps Questions (CVE-2021-25337)
FAQQ1. How critical is CVE-2021-25337 and is it actively exploited in the wild?
CVE-2021-25337 is rated CVSS 7.1 (HIGH) with a 30-day EPSS exploitation probability of 2.8%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2021-25337?
Primary impacted vendors include samsung across android, clipboard service. Scope summary: All Samsung Android smartphones and tablets with security patch levels prior to Samsung Security Maintenance Release (SMR) March 2021 Release 1
Q3. What temporary mitigations or workarounds exist for CVE-2021-25337 before patching?
[Mitigation] Immediately apply the official Samsung security update (SMR Mar-2021 Release 1 or later) Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
Generate an Internal Engineering Notice or CISO Report for CVE-2021-25337
Instantly format this advisory into an executive CISO summary or engineering patch ticket.
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