CVE-2015-1769
Microsoft Windows Mount Manager Privilege Escalation Vulnerability
Description
CVE-2015-1769 is a privilege escalation vulnerability in the Windows Mount Manager component caused by improper processing of symbolic links. An attacker who successfully exploits this vulnerability can escalate their privileges on the affected Windows system by leveraging the Mount Manager's failure to properly validate symbolic link targets. The vulnerability can be exploited through specially crafted USB devices or by creating malicious symbolic links on the file system. CISA has listed CVE-2015-1769 in the Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild, and its EPSS percentile of 96.7% indicates a very high probability of exploitation activity.
KEV Information
CVSS Score
CVSS:3.1/AV:P/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| microsoft | windows 10 | - |
| microsoft | windows 7 | - |
| microsoft | windows 8 | - |
| microsoft | windows 8.1 | - |
| microsoft | windows rt | - |
| microsoft | windows rt 8.1 | - |
| microsoft | windows server 2008 | -; r2 |
| microsoft | windows server 2012 | -; r2 |
| microsoft | windows vista | - |
References
- http://blogs.technet.com/b/srd/archive/2015/08/11/defending-against-cve-2015-1769-a-logical-issue-exploited-via-a-malicious-usb-stick.aspx(Vendor Advisory)
- http://www.securitytracker.com/id/1033244(Third Party Advisory, VDB Entry)
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-085(Patch, Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2015-1769(US Government Resource)
Weakness Type
No specific CWE has been assigned to CVE-2015-1769 in the NVD database. The vulnerability involves improper processing of symbolic links by the Windows Mount Manager component. Symbolic link vulnerabilities occur when a system component follows symbolic links without properly verifying their targets, allowing an attacker to redirect file system operations to unintended locations. In the Mount Manager, this enables an attacker to manipulate the mounting process to gain access to privileged resources or execute code with elevated permissions.
Learn more: CWE Overview
Impact Analysis
CVE-2015-1769 enables privilege escalation through the Windows Mount Manager's improper handling of symbolic links. The vulnerability can be exploited locally, including through physical access via USB devices. Confidentiality (High): Privilege escalation grants the attacker access to protected system files, credentials, and data belonging to other users that would normally be inaccessible. Integrity (High): With elevated privileges, an attacker can write to protected system locations, install persistent malware, modify security configurations, and manipulate critical system files. Availability (High): An attacker with escalated privileges can disrupt system operations, disable security services, or corrupt the file system. With an EPSS percentile of 96.7%, this vulnerability has a very high probability of active exploitation, particularly concerning for environments where USB devices are permitted or where local user access is broadly granted.
Exploit Maturity
CISA has confirmed active exploitation of CVE-2015-1769 by listing it in the Known Exploited Vulnerabilities catalog, with a remediation deadline of June 15, 2022. The EPSS percentile of 96.7% indicates a very high likelihood of exploitation. The symbolic link processing vulnerability in the Windows Mount Manager is particularly notable because it can be triggered via USB devices, making it exploitable through physical access without requiring network-based initial access. This makes CVE-2015-1769 valuable in scenarios involving insider threats, physical intrusion, or supply chain attacks through tampered USB devices.
Remediation
- Apply Microsoft security updates per vendor instructions as required by the CISA KEV catalog. Install all relevant patches that address CVE-2015-1769 in the Windows Mount Manager.
- Restrict USB device access using Group Policy or endpoint management tools. Implement USB device whitelisting to only allow approved storage devices, and consider disabling USB mass storage entirely on sensitive systems.
- Implement symbolic link protections by enabling the Windows security settings that restrict symbolic link creation to administrators only. Ensure that the Mount Manager cannot be tricked into following malicious symbolic links.
- Deploy endpoint detection and response (EDR) solutions capable of detecting unusual Mount Manager activity, suspicious symbolic link creation, and privilege escalation attempts.
- Enforce physical security controls for systems in sensitive environments. Restrict physical access to servers and workstations, and implement tamper-evident measures for USB ports on critical systems.
Technical Details
CVE-2015-1769 is a privilege escalation vulnerability in the Windows Mount Manager (mountmgr.sys) component. The vulnerability arises from improper processing of symbolic links during the mount operations handled by the Mount Manager. When the Mount Manager encounters a symbolic link during volume mounting or device enumeration, it follows the link without adequately verifying the target, allowing an attacker to redirect operations to unintended file system locations. This can be exploited by creating a crafted symbolic link that points to a privileged location, causing the Mount Manager to perform operations with elevated privileges at the attacker-specified target. The vulnerability is particularly relevant in the context of USB device insertion, where the Mount Manager processes device mount requests and can be tricked through specially crafted symbolic link structures on the device.
Frequently Asked Questions
Is CVE-2015-1769 being actively exploited?
Yes, CVE-2015-1769 is actively exploited. CISA confirmed its inclusion in the Known Exploited Vulnerabilities catalog with a remediation deadline of June 15, 2022. The EPSS percentile of 96.7% indicates very high exploitation probability.
What products are affected by CVE-2015-1769?
CVE-2015-1769 affects Microsoft Windows through the Mount Manager component. Multiple Windows versions are affected. Organizations should consult Microsoft security bulletins for specific version details and available patches.
How do I fix CVE-2015-1769?
Apply Microsoft security updates addressing this vulnerability. Restrict USB device access through Group Policy, implement symbolic link protections, and deploy endpoint detection solutions. Consider disabling USB mass storage on sensitive systems.
How severe is CVE-2015-1769?
CVE-2015-1769 is a privilege escalation vulnerability with an EPSS percentile of 96.7%. The vulnerability is particularly concerning because it can be triggered via USB devices, enabling exploitation through physical access without requiring network-based initial access.
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