Microsoft Windows Mount Manager Privilege Escalation Vulnerability (CVE-2015-1769)
Published In CISA KEV since Sources: CVE.org
What is affected, what to do
Mount Manager in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT Gold and 8.1, and Windows 10 mishandles symlinks, which allows physically proximate attackers to execute arbitrary code by connecting a crafted USB device, aka "Mount Manager Elevation of Privilege Vulnerability."
The vulnerability is being actively exploited; treat it as a priority. The available sources name no fixed version. Check the vendor guidance in the references below. Immediate actions, mitigation and detection rules are in the runbook below.
- Affected
- Microsoft Windows Server 2008
eq r2..r2 - Microsoft Windows Server 2012
eq r2..r2
- Microsoft Windows Server 2008
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Metrics
6.6
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: Vendor (CNA), CVSS v3
6.6
CVSS v3
Severity Medium on the scale from 0 to 10.
Source: CVE.org
4.1 %
EPSS score
Moderate — model estimates 1-10% exploitation likelihood.
Source: FIRST EPSS, percentile 90.7
Show all metrics
- Severity
- Critical
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 198.75 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- actively exploited
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 6.6 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 6.6
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 4.1 %
- Moderate — model estimates 1-10% exploitation likelihood.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 90.7
- Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- Actively exploited
- Published
In CISA KEV since
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- CISA assessment (SSVC)
- Exploitation: active · not automatable · Technical impact: total
- Source: CISA Vulnrichment, as of 10 February 2025
Response and mitigation
Why act now?
Prioritisation rationale
This flaw is on KEV because crafted USB devices can abuse Mount Manager's broken symlink handling to run code with elevated privileges — a classic vector for targeted intrusions against physically accessible or air-gapped systems. Exploitation needs physical proximity and a low-privileged local session, but then yields full compromise of confidentiality, integrity and availability; exploitation likelihood is notably high for a physical-vector bug, and CISA does not flag known ransomware use. For most patched office estates this rates medium priority; it becomes high to critical for unpatched legacy hosts, publicly accessible workstations, and OT/critical-infrastructure sites where USB is the primary data transfer path.
Runbook step 1
Immediate response (0-24 h)
- Verify patch status: Microsoft has released a security update for this Mount Manager flaw. Patch available from the vendor — look up the KB number and build in the vendor advisory for CVE-2015-1769. Reconcile installation status via WSUS/ConfigMgr/Intune compliance reports across all Windows clients and servers.
- Hunt down legacy systems: Windows Vista, 7, 8, 8.1, RT/RT 8.1 and Server 2008/2008 R2 are end-of-life. Flag any host lacking the update or ESU coverage as high-risk in the asset inventory and patch or replace it first.
- Physically exposed systems first: kiosks, reception PCs, control-room and HMI workstations, meeting-room PCs, branch-office and shop-floor machines — anywhere third parties can reach USB ports unattended — go into the first patch wave.
- Block USB mass storage now wherever operations allow: GPO "Prevent installation of devices not described by other policy settings" or EDR device control (e.g. Defender for Endpoint Device Control) set to Deny for removable storage.
- Triage suspected hosts: on physically accessible machines, review
HKLM\SYSTEM\MountedDevicesand USB history (HKLM\SYSTEM\CurrentControlSet\Enum\USBSTOR) for unknown devices.
Runbook step 2
Mitigation layers
- Physical security: USB port locks/blockers on unattended endpoints, chassis seals, access control for server rooms and cabinets; password-protect BIOS/UEFI and disable USB boot.
- Device control (GPO/MDM): allowlist by hardware/instance ID for approved devices (keyboard, mouse, managed encrypted drives); block the Disk Drives class
{53f56307-b6bf-11d0-94f2-00a0c91efb8b}and WPD otherwise. Also enforce "Removable Disks: Deny execute access". - Disable AutoRun/AutoPlay: enforce
HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer\NoDriveTypeAutoRun = 0xFFandNoAutorun = 1via GPO. - Endpoint hardening: application control (WDAC/AppLocker) denying execution from removable media; enable the ASR rule "Block untrusted and unsigned processes that run from USB".
- Least privilege: keep local accounts on kiosk/shared systems minimally privileged, avoid auto-logon, enforce short screen-lock timeouts — exploitation requires a low-privileged session on the device.
- OT/critical infrastructure: where patching is impossible, route all media through a scanning kiosk as the only permitted data path and disable USB on HMIs entirely.
Runbook step 3
Detection rules
- Windows Security Event ID 6416 (enable Audit PNP Activity): new external device recognised. Sigma shape:
EventID: 6416 AND ClassName: DiskDrive, weighted by host criticality; alert on kiosk/HMI/server assets. - Mount Manager registry writes: Sysmon EID 13 on
TargetObject|startswith: 'HKLM\System\MountedDevices\'outside maintenance windows. KQL:DeviceRegistryEvents | where RegistryKey has "MountedDevices" | summarize count() by DeviceName, bin(Timestamp,1h). - Execution from removable media: Sysmon EID 1 / Event 4688 where
Imageresides on a non-system drive (e.g.E:\,F:\), or processes atIntegrityLevel: Systemwith an unusual parent shortly after a USB mount (e.g. Explorer child → SYSTEM shell). - Removable storage auditing: Event ID 4663 (Audit Removable Storage) for write/execute access, plus
Microsoft-Windows-Partition/DiagnosticEvent 1006 to capture serial numbers of attached media. - EDR correlation: Defender
DeviceEvents | where ActionType == "UsbDriveMounted"followed within 10 minutes byProcessCreatedwithAccountName == "SYSTEM"and an unknown hash.
- Windows Security Event ID 6416 (enable Audit PNP Activity): new external device recognised. Sigma shape:
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
Mount Manager in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT Gold and 8.1, and Windows 10 mishandles symlinks, which allows physically proximate attackers to execute arbitrary code by connecting a crafted USB device, aka "Mount Manager Elevation of Privilege Vulnerability."
Source: NVD (NIST), cvelistv5, CISA KEV Catalog, CVE.org (MITRE)
Vendors and products
- Microsoft Microsoft Windows 10
- Microsoft Microsoft Windows 7
- Microsoft Microsoft Windows 8 Professional Edition
- Microsoft Microsoft Windows 8.1
- Microsoft Microsoft Windows RT Gold
- Microsoft Microsoft Windows RT 8.1
- Microsoft Microsoft Windows Server 2008
- Microsoft Microsoft Windows Server 2012
- Microsoft Microsoft Windows Vista Gold on X64
Affected operating systems
| Windows | microsoft | windows_10 | — |
| Windows | microsoft | windows_7 | — |
| Windows | microsoft | windows_8 | — |
| Windows | microsoft | windows_8.1 | — |
| Windows | microsoft | windows_rt | — |
| Windows | microsoft | windows_rt_8.1 | — |
| Windows | microsoft | windows_server_2008 | r2 |
| Windows | microsoft | windows_server_2008 | — |
| Windows | microsoft | windows_server_2012 | r2 |
| Windows | microsoft | windows_server_2012 | — |
| Windows | microsoft | windows_vista | — |
Public exploit references
Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.
| CISA KEV Catalog | CISA Known Exploited Vulnerability (opens in a new tab)cisa.gov | actively exploited |
References & sources
- blogs.technet.comb/srd/archive/2015/08/11/defending-against-cve-2015-1769-a-logi…x_refsource_CONFIRM, Vendor advisory
- docs.microsoft.comMS15-085Vendor advisory, x_refsource_MS, Patch, Vendor advisory
- securitytracker.com1033244Vulnerability database, x_refsource_SECTRACK, Third-party advisory, Vulnerability database
- cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2015-1769government-resource, US government resource
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<a href="https://intel.neosec.eu/en/cve/CVE-2015-1769"><img src="https://intel.neosec.eu/badge/cve/CVE-2015-1769.svg?lang=en" alt="CVE-2015-1769 – NEOSEC Intel" height="20"></a>