CriticalCVE-2022-22047

    Windows Client Server Run-time Subsystem (CSRSS) Elevation of Privilege Vulnerability (CVE-2022-22047)

    Published In CISA KEV since Sources: SingCERT, CVE.org

    What is affected, what to do

    Windows Client Server Run-time Subsystem (CSRSS) Elevation of Privilege Vulnerability

    The vulnerability is being actively exploited; treat it as a priority. Update Microsoft Windows 10 Version 1809 to version 10.0.17763.3165, Microsoft Windows Server 2019 to version 10.0.17763.3165, Microsoft Windows Server 2019 (Server Core installation) to version 10.0.17763.3165. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Microsoft Windows 10 Version 1809 lt 10.0.17763.0..10.0.17763.3165
    • Microsoft Windows Server 2019 lt 10.0.17763.0..10.0.17763.3165
    • Microsoft Windows Server 2019 (Server Core installation) lt 10.0.17763.0..10.0.17763.3165
    • Microsoft Windows 10 Version 21H1 lt 10.0.0..10.0.19043.1826
    • Microsoft Windows Server 2022 lt 10.0.20348.0..10.0.20348.825
    • Microsoft Windows 10 Version 20H2 lt 10.0.0..10.0.19042.1826
    • Microsoft Windows Server version 20H2 lt 10.0.0..10.0.19042.1826
    • Microsoft Windows 11 version 21H2 lt 10.0.0..10.0.22000.795
    • Microsoft Windows 10 Version 21H2 lt 10.0.19043.0..10.0.19044.1826
    • Microsoft Windows 10 Version 1507 lt 10.0.10240.0..10.0.10240.19360
    • Microsoft Windows 10 Version 1607 lt 10.0.14393.0..10.0.14393.5246
    • Microsoft Windows Server 2016 lt 10.0.14393.0..10.0.14393.5246
    • Microsoft Windows Server 2016 (Server Core installation) lt 10.0.14393.0..10.0.14393.5246
    • Microsoft Windows 7 lt 6.1.0..6.1.7601.26022
    • Microsoft Windows 7 Service Pack 1 lt 6.1.0..6.1.7601.26022
    • Microsoft Windows 8.1 lt 6.3.0..6.3.9600.20478
    • Microsoft Windows Server 2008 Service Pack 2 lt 6.0.6003.0..6.0.6003.21569
    • Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) lt 6.0.6003.0..6.0.6003.21569
    • Microsoft Windows Server 2008 R2 Service Pack 1 lt 6.1.7601.0..6.1.7601.26022
    • Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) lt 6.1.7601.0..6.1.7601.26022
    • Microsoft Windows Server 2012 lt 6.2.9200.0..6.2.9200.23771
    • Microsoft Windows Server 2012 (Server Core installation) lt 6.2.9200.0..6.2.9200.23771
    • Microsoft Windows Server 2012 R2 lt 6.3.9600.0..6.3.9600.20478
    • Microsoft Windows Server 2012 R2 (Server Core installation) lt 6.3.9600.0..6.3.9600.20478
    Fixed in
    • Microsoft Windows 10 Version 1809 10.0.17763.3165
    • Microsoft Windows Server 2019 10.0.17763.3165
    • Microsoft Windows Server 2019 (Server Core installation) 10.0.17763.3165
    • Microsoft Windows 10 Version 21H1 10.0.19043.1826
    • Microsoft Windows Server 2022 10.0.20348.825
    • Microsoft Windows 10 Version 20H2 10.0.19042.1826
    • Microsoft Windows Server version 20H2 10.0.19042.1826
    • Microsoft Windows 11 version 21H2 10.0.22000.795
    • Microsoft Windows 10 Version 21H2 10.0.19044.1826
    • Microsoft Windows 10 Version 1507 10.0.10240.19360
    • Microsoft Windows 10 Version 1607 10.0.14393.5246
    • Microsoft Windows Server 2016 10.0.14393.5246
    • Microsoft Windows Server 2016 (Server Core installation) 10.0.14393.5246
    • Microsoft Windows 7 6.1.7601.26022
    • Microsoft Windows 7 Service Pack 1 6.1.7601.26022
    • Microsoft Windows 8.1 6.3.9600.20478
    • Microsoft Windows Server 2008 Service Pack 2 6.0.6003.21569
    • Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) 6.0.6003.21569
    • Microsoft Windows Server 2008 R2 Service Pack 1 6.1.7601.26022
    • Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) 6.1.7601.26022
    • Microsoft Windows Server 2012 6.2.9200.23771
    • Microsoft Windows Server 2012 (Server Core installation) 6.2.9200.23771
    • Microsoft Windows Server 2012 R2 6.3.9600.20478
    • Microsoft Windows Server 2012 R2 (Server Core installation) 6.3.9600.20478

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    7.8

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    7.8

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: SingCERT, CVE.org

    18.8 %

    EPSS score

    Elevated — model estimates 10-50% exploitation likelihood.

    Source: FIRST EPSS, percentile 97.3

    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
    215.79 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
    7.8 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
    7.8
    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
    18.8 %
    Elevated — model estimates 10-50% 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
    97.3
    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 16 July 2024
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-426

    Response and mitigation

    Why act now?

    Prioritisation rationale

    CVE-2022-22047 was fixed as a zero-day on July 2022 Patch Tuesday and added to KEV the same day. Attackers chain it behind an initial foothold, such as a document or browser exploit, to reach SYSTEM. From there they disable security tooling, harvest credentials and establish persistence. The flaw is not network-reachable and needs local access with low privileges, but it requires no user interaction and yields full host compromise. Its exploitation likelihood is high relative to the CVE population, and CISA does not flag ransomware use. Fully patched estates only need compliance verification. Treat it as high priority wherever unpatched Windows 10/11 clients or non-ESU Windows 7 hosts remain, particularly user-facing machines with internet and email access.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Deploy Microsoft's July 2022 cumulative security update to all Windows clients and verify the target build: Windows 10 1507 ≥ 10.0.10240.19360, 1607 ≥ 10.0.14393.5246, 1809 ≥ 10.0.17763.3165, 20H2/21H1/21H2 ≥ 10.0.19042/19043/19044.1826, Windows 11 21H2 ≥ 10.0.22000.795. Look up the per-build KB number in the MSRC advisory for CVE-2022-22047.
      • Windows 7 (target build 6.1.7601.26022) only receives the fix via ESU. Treat non-ESU Windows 7 hosts as permanently vulnerable and isolate or retire them first.
      • Windows Server editions are not listed in this context but share the CSRSS codebase. Confirm their exposure and patch level in the vendor advisory, with priority on terminal servers and RDS hosts that carry many interactive users.
      • Query patch compliance through Intune, WSUS, SCCM or your asset inventory, for example the build revision in HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\UBR. Raise escalated tickets for every non-compliant device.
      • This is a local privilege escalation, so an initial foothold usually comes first. On unpatched hosts, re-triage any EDR alerts since July 2022 (phishing payloads, browser exploits, droppers) for follow-on SYSTEM-level activity.

    2. Runbook step 2

      Mitigation layers

      • Endpoint hardening: Microsoft documents no workaround, because CSRSS is a critical system process that cannot be disabled. Compensate by blocking the initial code execution: WDAC/AppLocker in enforce mode for user-writable paths (%APPDATA%, %TEMP%, Downloads), plus the ASR rules that block Office child processes and execution of downloaded scripts.
      • Credential protection: Enable LSA protection (RunAsPPL) and Credential Guard. They do not stop the escalation itself, but they limit the credential dumping that typically follows a SYSTEM compromise.
      • IAM/least privilege: Remove local admin rights and use LAPS. Keep tier-0 accounts off unpatched clients, and restrict interactive logon of privileged accounts on workstations via GPO (Deny log on locally).
      • Network segmentation: Move unpatched legacy hosts, especially Windows 7 without ESU, into a dedicated VLAN. Block SMB (445), RDP (3389) and WinRM (5985/5986) from that segment toward client and server networks to contain lateral movement after a successful escalation.
      • EDR configuration: Run in block mode rather than audit and enable tamper protection, so an attacker holding SYSTEM cannot trivially kill the agent.

    3. Runbook step 3

      Detection rules

      • Sysmon EID 1 / Security 4688: csrss.exe practically never spawns child processes in normal operation. Any child (cmd.exe, powershell.exe, rundll32.exe) is high-fidelity. KQL: DeviceProcessEvents | where InitiatingProcessFileName =~ "csrss.exe".
      • Integrity jump: Look for System-integrity processes whose ancestry traces back to a medium-integrity user process, especially when the parent is not services.exe or svchost.exe. Sigma shape: selection: IntegrityLevel: System, ParentUser|contains: <non-SYSTEM user>.
      • Sysmon EID 10 (ProcessAccess): Look for high-privilege handles to csrss.exe (GrantedAccess 0x1F0FFF, 0x1FFFFF) opened by non-system processes running from user-writable paths.
      • Sysmon EID 7 / EID 11: Alert on unsigned DLLs loaded into csrss.exe. As a hunting hypothesis, also flag unusual .manifest or .dll files written to %TEMP% or %APPDATA% shortly before an integrity jump.
      • Follow-on activity: On the same host, correlate the following within minutes of an unknown binary executing: Security 4672 or 4624 for SYSTEM, LSASS access (Sysmon EID 10, TargetImage lsass.exe), and new service installs (System 7045).

    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

    Windows Client Server Run-time Subsystem (CSRSS) Elevation of Privilege Vulnerability

    Source: CSA/SingCERT, NVD (NIST), cvelistv5, CISA KEV Catalog, CVE.org (MITRE)

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    MicrosoftWindows 10 Version 1507
    • 10.0.10240.0 – < 10.0.10240.19360
    • 10.0.10240.19360
    MicrosoftWindows 10 Version 1607
    • 10.0.14393.0 – < 10.0.14393.5246
    • 10.0.14393.5246
    MicrosoftWindows 10 Version 1809
    • 10.0.17763.0 – < 10.0.17763.3165
    • 10.0.17763.3165
    MicrosoftWindows 10 Version 20H2
    • 10.0.0 – < 10.0.19042.1826
    • 10.0.19042.1826
    MicrosoftWindows 10 Version 21H1
    • 10.0.0 – < 10.0.19043.1826
    • 10.0.19043.1826
    MicrosoftWindows 10 Version 21H2
    • 10.0.19043.0 – < 10.0.19044.1826
    • 10.0.19044.1826
    MicrosoftWindows 11 version 21H2
    • 10.0.0 – < 10.0.22000.795
    • 10.0.22000.795
    MicrosoftWindows 7
    • 6.1.0 – < 6.1.7601.26022
    • 6.1.7601.26022
    MicrosoftWindows 7 Service Pack 1
    • 6.1.0 – < 6.1.7601.26022
    • 6.1.7601.26022
    MicrosoftWindows 8.1
    • 6.3.0 – < 6.3.9600.20478
    • 6.3.9600.20478
    MicrosoftWindows Server 2008 R2 Service Pack 1
    • 6.1.7601.0 – < 6.1.7601.26022
    • 6.1.7601.26022
    MicrosoftWindows Server 2008 R2 Service Pack 1 (Server Core installation)
    • 6.1.7601.0 – < 6.1.7601.26022
    • 6.1.7601.26022
    MicrosoftWindows Server 2008 Service Pack 2
    • 6.0.6003.0 – < 6.0.6003.21569
    • 6.0.6003.21569
    MicrosoftWindows Server 2008 Service Pack 2 (Server Core installation)
    • 6.0.6003.0 – < 6.0.6003.21569
    • 6.0.6003.21569
    MicrosoftWindows Server 2012
    • 6.2.9200.0 – < 6.2.9200.23771
    • 6.2.9200.23771
    MicrosoftWindows Server 2012 (Server Core installation)
    • 6.2.9200.0 – < 6.2.9200.23771
    • 6.2.9200.23771
    MicrosoftWindows Server 2012 R2
    • 6.3.9600.0 – < 6.3.9600.20478
    • 6.3.9600.20478
    MicrosoftWindows Server 2012 R2 (Server Core installation)
    • 6.3.9600.0 – < 6.3.9600.20478
    • 6.3.9600.20478
    MicrosoftWindows Server 2016
    • 10.0.14393.0 – < 10.0.14393.5246
    • 10.0.14393.5246
    MicrosoftWindows Server 2016 (Server Core installation)
    • 10.0.14393.0 – < 10.0.14393.5246
    • 10.0.14393.5246
    MicrosoftWindows Server 2019
    • 10.0.17763.0 – < 10.0.17763.3165
    • 10.0.17763.3165
    MicrosoftWindows Server 2019 (Server Core installation)
    • 10.0.17763.0 – < 10.0.17763.3165
    • 10.0.17763.3165
    MicrosoftWindows Server 2022
    • 10.0.20348.0 – < 10.0.20348.825
    • 10.0.20348.825
    MicrosoftWindows Server version 20H2
    • 10.0.0 – < 10.0.19042.1826
    • 10.0.19042.1826

    Vendors and products

    Affected operating systems

    Affected operating systems
    Windowsmicrosoftwindows_10_1507—
    Windowsmicrosoftwindows_10_1607—
    Windowsmicrosoftwindows_10_1809—
    Windowsmicrosoftwindows_10_20h2—
    Windowsmicrosoftwindows_10_21h1—
    Windowsmicrosoftwindows_10_21h2—
    Windowsmicrosoftwindows_11_21h2—
    Windowsmicrosoftwindows_7—
    Windowsmicrosoftwindows_8.1—
    Windowsmicrosoftwindows_rt_8.1—
    Windowsmicrosoftwindows_server_2008r2
    Windowsmicrosoftwindows_server_2008—
    Windowsmicrosoftwindows_server_2012r2
    Windowsmicrosoftwindows_server_2012—
    Windowsmicrosoftwindows_server_2016—
    Windowsmicrosoftwindows_server_2019—
    Windowsmicrosoftwindows_server_2022—
    Windowsmicrosoftwindows_server_20h2—

    Weakness classes (CWE)

    • CWE-426Untrusted Search Path

      Base

      The product searches for critical resources using an externally-supplied search path that can point to resources that are not under the product's direct control.

      Entry at MITRE CWE-426

    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.

    Public exploit references
    CISA KEV CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited

    References & sources

    • Microsoft Security Update GuideWindows Client Server Run-time Subsystem (CSRSS) Elevation of Privilege VulnerabilityVendor advisory, Patch, Vendor advisory
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2022-22047government-resource, US government resource
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    Badge preview for CVE-2022-22047
    <a href="https://intel.neosec.eu/en/cve/CVE-2022-22047"><img src="https://intel.neosec.eu/badge/cve/CVE-2022-22047.svg?lang=en" alt="CVE-2022-22047 – NEOSEC Intel" height="20"></a>