CVE-2023-21492
Samsung Mobile Devices Insertion of Sensitive Information Into Log File Vulnerability
Description
CVE-2023-21492 is a medium-severity information disclosure vulnerability in Samsung mobile devices prior to the SMR May-2023 Release 1, where kernel pointers are improperly printed to log files. A privileged local attacker can exploit this flaw to obtain kernel memory addresses from device logs, enabling them to bypass Address Space Layout Randomization (ASLR) protections. ASLR bypass is a critical step in exploit chains, as it allows attackers to predict memory locations needed for subsequent code execution attacks. The vulnerability requires high privileges and local access, but it has been confirmed as actively exploited in the wild. With an EPSS score of 0.41% at the 60.6th percentile and its inclusion in CISA's Known Exploited Vulnerabilities catalog, CVE-2023-21492 represents a significant threat to Samsung devices, particularly when combined with other vulnerabilities in a multi-stage attack.
KEV Information
CVSS Score
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:NOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| samsung | android | 11.0; 12.0; 13.0 |
Multiple CVSS Assessments
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
References
- https://security.samsungmobile.com/securityUpdate.smsb?year=2023&month=05(Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-21492(US Government Resource)
Weakness Type
CWE-532: Insertion of Sensitive Information into Log File
CVE-2023-21492 is classified under CWE-532, where the Samsung Android kernel writes sensitive kernel pointer addresses to system log files. This weakness exposes internal memory layout information that should remain confidential, allowing attackers to derive the kernel base address and defeat ASLR protections. Log files are commonly accessible to privileged processes, making them a high-value target for information disclosure.
Learn more: CWE-532 — Insertion of Sensitive Information into Log File
Impact Analysis
Attack Vector (Local): CVE-2023-21492 requires local access to the Samsung device, meaning the attacker must already have some level of access to the device or leverage another vulnerability to gain initial access. Attack Complexity (Low): once local access and appropriate privileges are obtained, extracting kernel pointers from log files is straightforward with no special conditions required. Privileges Required (High): the attacker needs elevated privileges on the device to access the kernel log files containing the leaked pointer information. User Interaction (None): no action from the device owner is needed for exploitation once the attacker has the required access. Confidentiality (High): the vulnerability exposes kernel memory addresses that reveal the kernel base address, completely undermining ASLR protections and exposing the internal memory layout of the operating system. Integrity (None): the vulnerability itself does not allow modification of data or system configurations. Availability (None): exploitation does not directly impact device availability. With a CVSS score of 4.4 (Medium), CVE-2023-21492 may appear moderate in isolation, but its real danger lies in enabling exploit chains where ASLR bypass is a prerequisite for achieving kernel code execution through other vulnerabilities.
Exploit Maturity
Active exploitation has been confirmed for CVE-2023-21492. CISA has added this vulnerability to its Known Exploited Vulnerabilities catalog with a required remediation date of June 9, 2023, indicating that federal agencies were mandated to patch or mitigate within a tight timeline. Samsung acknowledged the vulnerability and provided a fix in the SMR May-2023 Release 1 security update. The EPSS score of 0.41% at the 60.6th percentile reflects the relatively narrow exploitation conditions (local access with high privileges), but the confirmed active exploitation indicates that threat actors are incorporating this ASLR bypass into real-world attack chains targeting Samsung devices. This vulnerability is likely used in conjunction with other flaws to achieve full device compromise in targeted surveillance or espionage operations.
Remediation
- Apply the Samsung SMR May-2023 security update: Update all Samsung mobile devices to the SMR May-2023 Release 1 or later, which removes kernel pointer logging from system log files. Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. CISA required remediation by June 9, 2023.
- Enable automatic security updates: Configure Samsung devices to automatically install monthly security maintenance releases (SMR) to ensure timely protection against newly disclosed vulnerabilities.
- Implement mobile device management (MDM) policies: Use MDM solutions to enforce security update compliance across all Samsung devices in the organization, ensuring no devices remain on vulnerable firmware versions.
- Restrict privileged access and debug logging: Review and restrict which applications and services have elevated privileges on managed devices. Disable verbose kernel logging on production devices where debug-level logging is not required.
- Monitor for exploit chain indicators: Watch for signs of targeted exploitation combining this ASLR bypass with other Samsung or Android kernel vulnerabilities. Review device security logs for suspicious privilege escalation patterns or unusual process behavior that may indicate a multi-stage attack.
Technical Details
CVE-2023-21492 is an information disclosure vulnerability (CWE-532: Insertion of Sensitive Information into Log File) in Samsung Android devices running firmware prior to the SMR May-2023 Release 1. The flaw occurs because the Samsung kernel writes kernel memory pointer values to system log files in a human-readable format, inadvertently exposing the kernel's virtual memory addresses. The CVSS vector (AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N) indicates that exploitation requires local access with high privileges, but once these prerequisites are met, the attack is straightforward with high confidentiality impact. The scope is unchanged, limiting the disclosure to information within the kernel's own security context. By reading these kernel pointers from log files, an attacker can calculate the kernel base address and effectively bypass ASLR, which randomizes memory locations to prevent predictable exploitation. ASLR bypass is a critical primitive in modern exploit development, as it allows the attacker to construct reliable return-oriented programming (ROP) chains or other memory corruption exploits that depend on knowing exact memory addresses. Samsung addressed this issue by removing or masking kernel pointer output in log files, following the established Linux kernel practice of using %pK format specifiers that hide pointer values from unprivileged readers.
Frequently Asked Questions
Is CVE-2023-21492 being actively exploited?
Yes, CVE-2023-21492 is actively exploited in the wild. CISA has added it to the Known Exploited Vulnerabilities catalog with a remediation deadline of June 9, 2023. The vulnerability is used in real-world attack chains as an ASLR bypass primitive to enable further exploitation of Samsung mobile devices.
What products are affected by CVE-2023-21492?
CVE-2023-21492 affects Samsung mobile devices running Android firmware prior to the SMR May-2023 Release 1. All Samsung smartphones and tablets that receive Samsung security maintenance releases and have not been updated to the May 2023 patch level are potentially vulnerable.
How do I fix CVE-2023-21492?
Update Samsung mobile devices to the SMR May-2023 Release 1 or later through the device Settings > Software Update menu or via Samsung MDM solutions. This update removes kernel pointer logging that enables the ASLR bypass.
How severe is CVE-2023-21492?
CVE-2023-21492 has a CVSS score of 4.4 (Medium severity) with high confidentiality impact. While the vulnerability alone only leaks kernel memory addresses, it serves as a critical enabler for exploit chains that achieve full device compromise. Its inclusion in CISA's KEV catalog underscores its significance in real-world targeted attacks against Samsung devices.
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