CriticalCVE-2023-24489

    Citrix Content Collaboration ShareFile Improper Access Control Vulnerability (CVE-2023-24489)

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

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    What is affected, what to do

    A vulnerability has been discovered in the customer-managed ShareFile storage zones controller which, if exploited, could allow an unauthenticated attacker to remotely compromise the customer-managed ShareFile storage zones controller.

    The vulnerability is being actively exploited; treat it as a priority. Update Citrix ShareFile Storage Zones Controller to version 5.11.24. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Citrix ShareFile Storage Zones Controller lt *..5.11.24
    Fixed in
    • Citrix ShareFile Storage Zones Controller 5.11.24

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

    Metrics

    9.8

    Priority

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

    Source: NVD, CVSS v3

    9.8

    CVSS v3

    Severity Critical on the scale from 0 to 10.

    Source: SingCERT, pwn.watch, CVE.org

    97.3 %

    EPSS score

    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.

    Source: FIRST EPSS, percentile 99.90

    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
    231.81 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 exploitedSource: CSA/SingCERT How we classify
    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
    9.8 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
    9.8
    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“.

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    97.3 %
    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
    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
    99.90
    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 · automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 27 January 2025
    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-284

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This flaw is network-reachable, requires neither authentication nor user interaction, and yields remote code execution on a system whose purpose is to broker file storage — meaning direct access to potentially personal and business-critical data. Exploitation likelihood is among the very highest tracked by EPSS; public PoCs have been available since July 2023 and are routinely used in opportunistic internet scanning. Typical targets are SMEs and enterprises running on-premises StorageZone controllers, often for regulated workloads in legal, healthcare, and public-sector contexts — the exact NIS2 and KRITIS audience. Treat this as P1: emergency patching within 24 hours, even though CISA has not flagged confirmed ransomware use, because the path from exploit to data exfiltration and AD lateral movement fully justifies the top priority.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Deploy Citrix ShareFile Storage Zones Controller 5.11.24 (or later) on every customer-managed StorageZone host; follow vendor advisory CTX559517. All 5.10.x and earlier 5.11.x builds are vulnerable.
      • Review internet exposure immediately: restrict HTTPS/443 to the StorageZone controllers behind a WAF or source-IP allowlist; disconnect unpatched controllers from the internet until the update is verified in place.
      • Preserve IIS logs for the last 90 days before patching (the update overwrites artefacts). Copy C:\inetpub\logs\LogFiles\ and C:\inetpub\wwwroot\Citrix\StorageCenter\ to offline storage for forensics.
      • Rotate credentials used by the StorageZone controller service account and the SQL account for CitrixAccessPlatform/ConfigService; assume compromise on any host that was internet-exposed and unpatched.
      • Inspect C:\inetpub\wwwroot\Citrix\StorageCenter\, in particular the documentum\ subtree, for unexpected .aspx files and compare hashes against a clean reference build.
      • Open an incident ticket (NIS2 notification potentially required if data egress is plausible); set the timeline baseline to July 2023 when public exploitation emerged.

    2. Runbook step 2

      Mitigation layers

      • Network segmentation: place StorageZone controllers in a dedicated DMZ; inbound TCP/443 only from the Citrix control plane and authorised clients. Default-deny outbound with an explicit allowlist to *.sharefile.com.
      • WAF/reverse-proxy rule: block (or alert on) HTTP requests to /documentum/ carrying XML upload payloads, especially POSTs containing path-traversal patterns (..%2f, %252e) or .NET deserialisation markers (XML with __type / System.* tags).
      • Endpoint hardening: AppLocker/WDAC policy that allows only signed Citrix binaries under the IIS worker account (w3wp.exe in the StorageCenter app pool); block cmd.exe, powershell.exe, cscript.exe, wscript.exe as child processes of w3wp.exe.
      • IAM: run the StorageZone service account as a gMSA with minimal rights — no local admin, no domain admin — and restrict its SQL permissions to the required database roles.
      • Configuration: tighten IIS Request Filtering so that Content-Length is bounded and double-encoding is rejected (requestFiltering allowDoubleEscaping="false").
      • Monitoring: raise EDR enforcement on StorageZone hosts from detect to prevent, especially for script interpreters and common LOLBins (certutil, bitsadmin, mshta).

    3. Runbook step 3

      Detection rules

      • IIS access log (Sigma/KQL shape): cs-uri-stem contains /documentum/ with cs-method POST and an atypical User-Agent (python-requests, curl, empty) — high priority alert.
      • Sysmon EID 1 on StorageZone hosts: ParentImage = w3wp.exe with Image in (cmd.exe, powershell.exe, rundll32.exe, certutil.exe) — classic webshell signature.
      • Sysmon EID 11 (FileCreate): new .aspx, .ashx, or .asmx files beneath C:\inetpub\wwwroot\Citrix\StorageCenter\documentum\ outside scheduled deployment windows.
      • Suricata/Zeek: HTTP POST requests to URIs containing documentum with XML content-type and body size > 2 KB targeting the Citrix DMZ — alert on baseline deviation.
      • Windows Security EID 4624/4672: interactive or network logons from the StorageZone service account originating anywhere other than the Citrix control-plane IP range; correlate with EID 4688 for process creations under that account.
      • EDR process ancestry: w3wp.exe → cmd.exe → whoami / net user / nltest /dclist as a discovery chain should be a prioritised alert.

    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

    A vulnerability has been discovered in the customer-managed ShareFile storage zones controller which, if exploited, could allow an unauthenticated attacker to remotely compromise the customer-managed ShareFile storage zones controller.

    Source: CSA/SingCERT, pwn.watch, 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
    CitrixCitrix ShareFile Storage Zones Controller
    • < 5.11.24
    • 5.11.24
    citrixsharefile_storage_zones_controller
    • < 5.11.24
    • 5.11.24

    Vendors and products

    Weakness classes (CWE)

    • CWE-284Improper Access Control

      Pillar

      The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

      Entry at MITRE CWE-284

    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
    CSA/SingCERTCritical Vulnerability in Citrix ShareFile Storage Zones Controller (opens in a new tab)CSA/SingCERTactively exploited

    References & sources

    • support.citrix.comVendor advisory: Citrix Content CollaborationBroken link, Vendor advisory, pwn-watch
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2023-24489government-resource, US government resource
    • pwn.watchpwn.watch: Citrix Content Collaboration: ShareFile Improper Access Control (CVE-2023-24489)pwn-watch
    • NVD (NIST)NVD: CVE-2023-24489pwn-watch
    • cisa.govCISA Known Exploited Vulnerabilities Catalogpwn-watch
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