CVE-2023-21492

What it actually does

The vulnerability causes Samsung Android devices prior to the May 2023 Security Maintenance Release 1 to write kernel pointer values to logs. A privileged local attacker who can read those logs can recover kernel memory addresses and use them to bypass Kernel Address Space Layout Randomization (KASLR/ASLR). By itself, the flaw is an information disclosure issue and does not directly provide code execution or privilege escalation, but it materially weakens kernel exploit mitigations and is especially useful when chained with another local kernel or driver vulnerability.

Why it matters to the business

Affected Samsung Android devices may be easier to compromise if an attacker already has elevated local access or is exploiting another vulnerability on the device. Because this issue is listed in CISA KEV and has been observed as actively exploited in the wild, unpatched devices should be treated as higher risk even though the CVSS score is moderate. Successful exploitation can support device takeover chains, data theft, surveillance, persistence, and disruption of mobile operations. The CISA remediation deadline was 2023-06-09, so any still-vulnerable managed device is significantly overdue for remediation.

How an attack unfolds

An attacker first obtains a local execution foothold on an affected Samsung Android device, typically through a malicious application, another exploit, physical access, or abuse of already-granted elevated privileges. The attacker then reads system, kernel, or diagnostic logs that contain raw kernel pointer values. Those leaked addresses reveal where kernel code or data structures are located in memory, defeating address randomization defenses. With reliable kernel address knowledge, the attacker can tune a second-stage kernel exploit that would otherwise be unreliable or blocked by ASLR. In observed real-world exploitation contexts, this type of bug is most valuable as part of a chained mobile compromise rather than as a standalone exploit.

How to fix it

Update affected Samsung Android devices to Samsung SMR May-2023 Release 1 or later. Where available, deploy the latest vendor firmware/security update rather than only the minimum fixed level, because mobile exploit chains often rely on multiple vulnerabilities. Enforce mobile device management compliance rules that block or quarantine devices below the May 2023 patch level. If immediate patching is not possible, reduce exposure by restricting installation of untrusted applications, disabling developer options where not required, limiting physical access, preventing USB debugging, enforcing Play Protect or equivalent app reputation controls, and collecting mobile threat defense telemetry. There is no reliable configuration-only mitigation that fully removes the risk if the vulnerable firmware remains installed.

How to confirm the fix worked

Confirm each Samsung Android device reports an Android security patch level that includes Samsung SMR May-2023 Release 1 or a later Samsung security release. Validate through device settings, MDM inventory, EMM compliance posture, or vendor firmware build metadata. Confirm devices are not running pre-May-2023 Samsung firmware and that no vulnerable device remains allowed to access sensitive business services. For technical validation, review kernel/system logs after patching and verify that raw kernel pointer values are no longer emitted to ordinary log sources. Avoid treating absence of visible log leakage as proof of remediation unless firmware patch level is also confirmed.

Typical attack path

1. Gain local execution on an affected Samsung Android device through a malicious app, exploit chain, physical access, or existing elevated privilege.
2. Access device logs, kernel logs, crash logs, or diagnostic logs that contain kernel pointer values.
3. Extract leaked kernel memory addresses from the logs.
4. Use the leaked addresses to bypass ASLR/KASLR protections.
5. Launch or stabilize a follow-on kernel exploit or privilege-escalation technique.
6. Use the resulting access for persistence, surveillance, data theft, lateral movement through connected accounts, or further payload deployment.

How to detect it

Detecting prior exploitation is difficult because this flaw primarily leaks information and may not leave a unique event. Focus hunting on evidence that a local actor or malicious app collected kernel/system logs and then attempted privilege escalation. Relevant sources include Android logcat buffers, kernel logs, crash/tombstone files, MDM/EMM device telemetry, mobile threat defense alerts, app inventory, package install history, USB debugging/ADB activity, SELinux denial logs, and forensic filesystem artifacts. Look for unusual use of logcat or dmesg by non-administrative apps, repeated reads of kernel logs, raw kernel pointer patterns in logs, access to /proc/kallsyms or /dev/kmsg, suspicious native binaries dropped by apps, unexpected su/magisk/rooting artifacts, and exploit-chain behavior occurring shortly after log collection. Because this CVE is KEV-listed and actively exploited, any vulnerable device showing suspicious local privilege escalation, sideloaded malware, or abnormal log harvesting should be investigated as potentially compromised.

• logcat -b kernel
• logcat -b all
• dmesg
• /dev/kmsg
• /proc/kmsg
• /proc/kallsyms
• /sys/kernel/debug
• /data/tombstones/
• /data/anr/
• /data/local/tmp/
• avc: denied { read } for name="kmsg"
• avc: denied { open } for name="kallsyms"
• 0xffffff
• 0xfffffff
• kptr_restrict
• /system/bin/logcat
• /system/bin/dmesg
• /sbin/su
• /system/xbin/su
• /system/bin/su
• magiskd
• /data/adb/magisk/

What your security team should do

• Immediately identify all managed Samsung Android devices below the May 2023 security maintenance level and prioritize remediation because the issue is in CISA KEV and actively exploited in the wild.
• Require upgrade to Samsung SMR May-2023 Release 1 or later, preferably the latest available Samsung security update for each model.
• Quarantine or restrict access for devices that cannot be updated, especially those used by privileged users or for sensitive business applications.
• Hunt for signs of exploit chaining, suspicious log collection, local privilege escalation attempts, unknown sideloaded applications, USB debugging abuse, and anomalous mobile threat defense alerts.
• Review mobile application inventory for sideloaded, unknown, or high-risk apps with elevated permissions or suspicious behavior.
• Ensure MDM/EMM compliance policies enforce minimum Android/Samsung patch levels and block stale firmware from accessing corporate resources.
• Preserve logs and forensic artifacts from suspected compromised devices before factory reset or reimaging.
• For high-risk populations, consider mobile threat defense scanning and targeted forensic review rather than relying only on patch-status reporting.