CriticalCVE-2025-2775

    SysAid On-Prem <= 23.3.40 Checkin Proceessing XML External Entity Injection (CVE-2025-2775)

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

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    What is affected, what to do

    SysAid On-Prem versions <= 23.3.40 are vulnerable to an unauthenticated XML External Entity (XXE) vulnerability in the Checkin processing functionality, allowing for administrator account takeover and file read primitives.

    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
    • SysAid On-Prem lte *..23.3.40

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

    Metrics

    9.3

    Priority

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

    Source: Vendor (CNA), CVSS v3

    9.3

    CVSS v3

    Severity Critical on the scale from 0 to 10.

    Source: pwn.watch, CVE.org

    42.6 %

    EPSS score

    Elevated — model estimates 10-50% exploitation likelihood.

    Source: FIRST EPSS, percentile 98.7

    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
    233.26 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: VulnCheck KEV (opens in a new tab) 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.

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    9.3 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
    9.3
    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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    42.6 %
    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
    98.7
    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 · automatable · Technical impact: partial
    Source: CISA Vulnrichment, as of 22 July 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-611

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This CVE is on KEV because it is network-reachable without authentication and delivers both administrator takeover and arbitrary file read in a single request — and an ITSM platform like SysAid typically stores service-account credentials, integrations into AD/MDM, and ticket history containing sensitive data, making it a high-value pivot. Exploitation likelihood is very high, public PoC code exists, and SysAid on-prem installations have been actively targeted before (notably in 2023 by ransomware actors abusing different SysAid CVEs). Treat every internet-exposed SysAid On-Prem system as P1 and internally reachable instances as P2, especially in NIS2-regulated and KRITIS environments where SysAid is the central service-management tool.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Upgrade SysAid On-Prem to 23.3.41 or later immediately (per SysAid security bulletin; fix is carried into the 24.x branch). Any instance <= 23.3.40 is vulnerable.
      • If patching within 24 h is not feasible, remove the SysAid web interface from the internet — in particular block the /checkin endpoint at the reverse proxy / WAF. Restrict access to an internal management VLAN only.
      • After patching, rotate all SysAid administrator credentials and API tokens — account takeover is a documented impact, so treat existing sessions as compromised.
      • Audit which sensitive files were readable by the SysAid service account (e.g. serverConfig.xml, keystores, DB credentials, SSH keys). If logs show suspicious access, treat those secrets as leaked and rotate them.
      • Open an IR ticket scoped as "unauthenticated XXE, admin takeover" and preserve the last 90 days of web and application logs before rotation overwrites them.

    2. Runbook step 2

      Mitigation layers

      • Network segmentation: place the SysAid server in a dedicated management segment and block egress to arbitrary external HTTP/FTP/DTD hosts. XXE exfiltration typically relies on out-of-band channels; killing egress breaks the exploit chain.
      • WAF / reverse-proxy rule: inspect POST requests against the /checkin endpoint and drop any body containing <!DOCTYPE, <!ENTITY, SYSTEM "file: or SYSTEM "http:. Enforce strict handling of text/xml and application/xml content types on that path.
      • Enable generic XXE IPS signatures (Suricata/Snort rules matching DOCTYPE … ENTITY … SYSTEM) and bind them to the SysAid vhost.
      • Harden the SysAid service account: remove read access to /etc/shadow, keystore files, admin home directories; on Windows, tighten NTFS ACLs accordingly.
      • Put mTLS or an IP allow-list in front of the Checkin endpoint — legitimate check-ins come from a known set of agent IPs; drop everything else.
      • DNS monitoring: configure the egress resolver so that lookups from the SysAid host to non-business external domains are logged and alerted (OOB-XXE channel).

    3. Runbook step 3

      Detection rules

      • Web access logs on the SysAid host: POST to the Checkin URL with an unusually large body or content type application/xml from previously unseen source IPs. KQL shape: WebLogs | where UrlPath contains "checkin" and Method == "POST" and (RequestBody has "DOCTYPE" or RequestBody has "ENTITY").
      • Sysmon EID 3 (Network Connect) or Zeek conn.log: outbound connections from the SysAid server process (Java/Tomcat) to external IPs on ports 80/443/21 immediately after an inbound Checkin request — classic OOB-XXE pattern.
      • Sysmon EID 7/11: SysAid process touching sensitive files outside its install directory (C:\Windows\System32\config\, keystores, .ssh/). On Linux, auditd watch rules on /etc/passwd, /etc/shadow and keystore paths with subject = SysAid service UID.
      • SIEM correlation: within 60 s of a POST to /checkin, an administrative action appears in SysAid audit logs (new admin user, password reset, role change) — strong indicator of account takeover.
      • Sigma shape: detection: selection: web.url|contains: '/checkin' web.body|contains: ['<!DOCTYPE', '<!ENTITY', 'SYSTEM'] condition: selection as a baseline rule in the SIEM content library.

    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

    SysAid On-Prem versions <= 23.3.40 are vulnerable to an unauthenticated XML External Entity (XXE) vulnerability in the Checkin processing functionality, allowing for administrator account takeover and file read primitives.

    Source: 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
    SysAidSysAid On-Prem
    • ≤ 23.3.40
    • —
    sysaidsysaid
    • ≤ 23.3.40
    • —

    Vendors and products

    Weakness classes (CWE)

    • CWE-611Improper Restriction of XML External Entity Reference

      Base

      The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.

      Entry at MITRE CWE-611

    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
    Reference tagged as exploitlabs.watchtowr.com (opens in a new tab)PoC (publicly reported)reported, not verified—

    References & sources

    • documentation.sysaid.comSysAid advisory: SysAid On-PremVendor advisory, Release notes, pwn-watch
    • labs.watchtowr.comsysowned-your-friendly-rce-support-ticketExploit, Exploit, Third-party advisory
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2025-2775government-resource, US government resource
    • pwn.watchpwn.watch: SysAid On-Prem: 2 exploited vulnerabilities (CVE-2025-2775, CVE-2025-2776)pwn-watch
    • NVD (NIST)NVD: CVE-2025-2775pwn-watch
    • NVD (NIST)NVD: CVE-2025-2776pwn-watch
    • cisa.govCISA Known Exploited Vulnerabilities Catalogpwn-watch
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    Badge preview for CVE-2025-2775
    <a href="https://intel.neosec.eu/en/cve/CVE-2025-2775"><img src="https://intel.neosec.eu/badge/cve/CVE-2025-2775.svg?lang=en" alt="CVE-2025-2775 – NEOSEC Intel" height="20"></a>