CVE-2019-1388
Microsoft Windows Certificate Dialog Privilege Escalation Vulnerability
Description
CVE-2019-1388 is an elevation of privilege vulnerability in the Microsoft Windows Certificate Dialog that allows a low-privileged local user to gain SYSTEM-level access. The flaw occurs because the Windows Certificate Dialog does not properly enforce user privileges when handling certificate information. By exploiting this improper privilege management weakness, an attacker with local access and low-level privileges can escalate their permissions to gain full control over the affected Windows system. CISA has confirmed active exploitation of CVE-2019-1388 in the wild, with known use in ransomware campaigns, and the vulnerability affects a wide range of Microsoft Windows versions including Windows 7, 8.1, 10, and multiple Windows Server editions.
KEV Information
CVSS Score
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| microsoft | windows 10 1507 | - |
| microsoft | windows 10 1607 | - |
| microsoft | windows 10 1709 | - |
| microsoft | windows 10 1803 | - |
| microsoft | windows 10 1809 | - |
| microsoft | windows 10 1903 | - |
| microsoft | windows 7 | - |
| microsoft | windows 8.1 | - |
| microsoft | windows rt 8.1 | - |
| microsoft | windows server 1903 | - |
| microsoft | windows server 2008 | -; r2 |
| microsoft | windows server 2012 | -; r2 |
| microsoft | windows server 2016 | -; 1803 |
| microsoft | windows server 2019 | - |
Multiple CVSS Assessments
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
References
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1388(Patch, Vendor Advisory)
- https://www.zerodayinitiative.com/advisories/ZDI-19-975/(Third Party Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-1388(US Government Resource)
Weakness Type
CWE-269: Improper Privilege Management
The Windows Certificate Dialog in CVE-2019-1388 fails to properly manage and enforce user privilege levels when processing certificate information. This improper privilege management allows a local attacker to leverage the certificate dialog interface to execute actions at an elevated privilege level, bypassing the intended security boundaries between standard user and SYSTEM contexts.
Learn more: CWE-269 — Improper Privilege Management
Impact Analysis
CVE-2019-1388 is rated High severity with a CVSS v3.1 score of 7.8, reflecting the serious consequences of successful exploitation. The vulnerability requires local access to exploit, meaning an attacker must already have a foothold on the target system, but attack complexity is low and no user interaction is needed. Only low-level privileges are required to trigger the exploit, making it accessible to any authenticated user on the system. Confidentiality (High): Elevating to SYSTEM privileges grants the attacker unrestricted access to all data on the system, including credentials, security tokens, and protected files. Integrity (High): SYSTEM-level access allows modification of any system file, security policy, or configuration, enabling persistence and further compromise. Availability (High): An attacker with SYSTEM privileges can disable security controls, terminate processes, or render the system inoperable. The confirmed use of CVE-2019-1388 in ransomware campaigns demonstrates that threat actors actively leverage this privilege escalation to deploy ransomware with maximum impact after initial access.
Exploit Maturity
CVE-2019-1388 has been thoroughly analyzed by the security community, with a detailed advisory available from the Zero Day Initiative. CISA has confirmed active exploitation in the wild and this vulnerability is known to be used in ransomware campaigns, where attackers leverage the privilege escalation to deploy ransomware with SYSTEM-level access. The EPSS score of 7.5% (92nd percentile) indicates a high likelihood of exploitation relative to other vulnerabilities. This elevation of privilege vulnerability is commonly used as a post-exploitation tool after an attacker has gained initial low-privilege access to a Windows system through other means.
Remediation
- Apply vendor mitigations immediately as directed by CISA: "Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable." The CISA remediation deadline was April 28, 2023. Install the security update from the Microsoft Security Response Center advisory.
- Apply the Microsoft security patch to all affected Windows versions including Windows 7, Windows 8.1, Windows 10 (versions 1507 through 1903), Windows Server 2008, 2012, 2016, and 2019. Prioritize internet-facing and high-value systems.
- Restrict local access to Windows systems by enforcing the principle of least privilege. Review local user group memberships and remove unnecessary standard user accounts from systems that handle sensitive data or critical services.
- Monitor for privilege escalation attempts by enabling detailed Windows Security event logging, particularly Event IDs related to privilege use and process creation. Use endpoint detection and response (EDR) tools to alert on unexpected SYSTEM-level process creation from user-initiated certificate dialog interactions.
- Implement application control policies using Windows Defender Application Control or AppLocker to restrict which applications can be executed by standard users, reducing the attack surface for local privilege escalation techniques.
Technical Details
CVE-2019-1388 is classified as CWE-269 (Improper Privilege Management) and targets the Windows Certificate Dialog component. The vulnerability arises because the certificate dialog, when displaying certificate information to a user, does not properly enforce the privilege level under which subsequent actions are executed. The CVSS vector (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) confirms that while local access is required, the exploit is straightforward with low complexity and does not require user interaction beyond the attacker themselves. A low-privileged user can trigger the certificate dialog and manipulate the certificate information handling process to execute code with SYSTEM privileges. The scope remains unchanged, indicating the exploit operates within the Windows operating system context, but the high impact across confidentiality, integrity, and availability reflects complete system compromise once SYSTEM-level access is achieved.
Frequently Asked Questions
Is CVE-2019-1388 being actively exploited?
Yes, CVE-2019-1388 is actively exploited in the wild. CISA has listed it in the Known Exploited Vulnerabilities catalog with confirmed use in ransomware campaigns. The EPSS score of 7.5% (92nd percentile) further indicates a high probability of exploitation compared to most vulnerabilities.
What products are affected by CVE-2019-1388?
CVE-2019-1388 affects a wide range of Microsoft Windows products including Windows 7, Windows 8.1, Windows RT 8.1, Windows 10 (versions 1507, 1607, 1709, 1803, 1809, and 1903), and Windows Server editions 2008, 2012, 2016, and 2019 (including version 1903). All of these versions are vulnerable unless the Microsoft security patch has been applied.
How do I fix CVE-2019-1388?
Apply the security update provided by Microsoft through the MSRC advisory for CVE-2019-1388. This patch addresses the improper privilege enforcement in the Windows Certificate Dialog. For systems that cannot be immediately patched, restrict local access and implement enhanced monitoring for privilege escalation attempts.
How severe is CVE-2019-1388?
CVE-2019-1388 is rated High severity with a CVSS v3.1 score of 7.8 out of 10. While it requires local access rather than remote exploitation, the ability to escalate from a low-privileged user to SYSTEM-level access makes it a critical post-exploitation tool. Its use in ransomware campaigns confirms its real-world severity.
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