CVE-2023-21492: Samsung Android Privilege Escalation Flaw

CVE-2023-21492 Overview

CVE-2023-21492 is an information disclosure vulnerability in Samsung Android devices where kernel pointers are improperly printed to log files. This security flaw allows a privileged local attacker to obtain sensitive kernel memory addresses, effectively bypassing Address Space Layout Randomization (ASLR) protections. ASLR is a critical security mechanism that randomizes memory locations to prevent attackers from reliably exploiting memory corruption vulnerabilities.

Critical Impact

This vulnerability has been confirmed as actively exploited in the wild and is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog. Organizations using affected Samsung devices should prioritize immediate patching.

Affected Products

• Samsung Android 11.0 (all SMR releases prior to SMR-May-2023-R1)
• Samsung Android 12.0 (all SMR releases prior to SMR-May-2023-R1)
• Samsung Android 13.0 (all SMR releases prior to SMR-May-2023-R1)

Discovery Timeline

• May 4, 2023 - CVE-2023-21492 published to NVD
• October 28, 2025 - Last updated in NVD database

Technical Details for CVE-2023-21492

Vulnerability Analysis

This vulnerability (CWE-532: Insertion of Sensitive Information into Log File) occurs when the Samsung Android kernel writes pointer addresses to system log files. These kernel pointers reveal the memory layout of the kernel, which should remain unpredictable due to ASLR protections. By reading these log files, an attacker with privileged local access can determine exact kernel memory addresses, transforming what would otherwise be probabilistic exploitation attempts into deterministic attacks.

The vulnerability requires local access with elevated privileges, which limits the initial attack surface. However, in multi-stage attack scenarios, this information disclosure can serve as a crucial stepping stone for more severe kernel exploitation. Attackers commonly chain ASLR bypass vulnerabilities with memory corruption bugs to achieve reliable code execution in the kernel context.

Root Cause

The root cause lies in improper logging practices within the Samsung Android kernel or its proprietary components. Kernel code inadvertently uses format specifiers (such as %p or %px) that output raw pointer values to log files instead of using privacy-preserving alternatives. These log files are then accessible to processes with sufficient privileges, creating an information leak channel.

Secure coding practices dictate that kernel pointers should either not be logged or should be hashed/obscured when written to logs accessible by user-space processes. The Linux kernel provides the %pK format specifier specifically to handle this scenario, but the vulnerable Samsung code did not employ such safeguards.

Attack Vector

The attack requires local access to a Samsung Android device with elevated privileges. An attacker would:

1. Gain privileged access to the device through another vulnerability or by compromising a privileged application
2. Read system log files containing kernel pointer addresses
3. Analyze the leaked addresses to map out the kernel's memory layout
4. Use this information to defeat ASLR when exploiting a separate memory corruption vulnerability

The disclosed kernel addresses eliminate the randomization that ASLR provides, making subsequent exploitation significantly more reliable. This is particularly concerning for targeted attacks where attackers have specific Samsung devices they wish to compromise.

Detection Methods for CVE-2023-21492

Indicators of Compromise

• Unusual access patterns to system log files from non-system processes
• Processes attempting to read /dev/kmsg or other kernel log interfaces outside normal operations
• Evidence of privilege escalation followed by log file access on Samsung devices
• Memory corruption exploits targeting Samsung kernel components

Detection Strategies

• Monitor for anomalous log file access by applications that typically should not require such access
• Implement mobile device management (MDM) solutions that can detect and report device firmware versions
• Deploy endpoint detection capabilities that can identify exploitation chains targeting mobile devices
• Review application permissions for unnecessary access to system logs

Monitoring Recommendations

• Enable logging and alerting for privileged process creation on managed Samsung devices
• Track firmware and SMR (Samsung Maintenance Release) versions across your mobile device fleet
• Integrate mobile threat defense solutions with your SIEM to correlate mobile device anomalies
• Regularly audit enterprise applications deployed on Samsung devices for excessive permissions

How to Mitigate CVE-2023-21492

Immediate Actions Required

• Update all Samsung Android devices to SMR-May-2023-R1 or later immediately
• Prioritize devices with access to sensitive corporate data or systems
• Review and restrict applications with privileged access on Samsung devices
• Isolate unpatched Samsung devices from sensitive network segments until updates can be applied

Patch Information

Samsung has addressed this vulnerability in the SMR May-2023 Release 1 security maintenance release. The patch removes kernel pointer information from log files, preventing the information disclosure. Organizations should apply this update through their standard mobile device management processes. The official security advisory is available from Samsung Mobile Security.

Due to confirmed exploitation in the wild, CISA has added this vulnerability to their Known Exploited Vulnerabilities Catalog, mandating federal agencies to remediate within specified timeframes.

Workarounds

• Restrict physical access to affected Samsung devices to trusted personnel only
• Limit installation of applications that require elevated privileges
• Consider temporarily disabling USB debugging and other development features on affected devices
• Implement strict application allowlisting to reduce the attack surface for privilege escalation

# Verify Samsung device firmware version via ADB
adb shell getprop ro.build.version.security_patch
# Output should show 2023-05-01 or later for patched devices

# Check current SMR version
adb shell getprop ro.build.PDA