CriticalCVE-2023-38950

    ZKTeco BioTime Path Traversal Vulnerability (CVE-2023-38950)

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

    What is affected, what to do

    A path traversal vulnerability in the iclock API of ZKTeco BioTime v8.5.5 allows unauthenticated attackers to read arbitrary files via supplying a crafted payload. This vulnerability was fixed in version 9.0.120240617.19506 of ZKBioTime.

    The vulnerability is being actively exploited; treat it as a priority. Update ZKTeco BioTime to version 9.0.1. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • ZKTeco BioTime lt *..9.0.1
    Fixed in
    • ZKTeco BioTime 9.0.1

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

    Metrics

    7.5

    Priority

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

    Source: NVD, CVSS v3

    7.5

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: pwn.watch, CVE.org

    92.5 %

    EPSS score

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

    Source: FIRST EPSS, percentile 99.82

    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
    220.38 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
    7.5 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
    7.5
    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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    92.5 %
    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
    99.82
    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 21 May 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-22

    Response and mitigation

    Why act now?

    Prioritisation rationale

    The flaw is network-reachable, requires no authentication and yields arbitrary file read on a system that typically holds personal access data, biometric templates and database credentials — placing it squarely in GDPR and NIS2 scope. The CISA-KEV listing together with a very high exploitation likelihood show that attackers are actively scanning the iclock API at scale; ransomware-campaign use is not confirmed, but arbitrary read is a classic initial-access and credential-harvesting primitive that frequently precedes lateral movement. Treat every internet-facing BioTime instance as P1; internally reachable instances as P2 with a patch window of 72 hours or less, because physical access-control systems often bridge IT and OT segments in KRITIS environments.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Upgrade ZKTeco BioTime to version 9.0.120240617.19506 or later; every build from v8.5.5 up to and including 9.0.1 is vulnerable.
      • Remove the BioTime web UI and the iclock API endpoint from the public internet via perimeter firewall / reverse proxy; restrict access to a dedicated management VLAN.
      • At the reverse proxy or WAF, block unauthenticated access to iclock paths (typically under /iclock/) until patching is complete.
      • Reduce the OS privileges of the BioTime service account to the minimum required (no read access to /etc/shadow, backups, certificate stores, or configuration of other services).
      • Rotate every credential stored in BioTime configuration files (database, SMTP, LDAP bind, API keys) — an unauthenticated arbitrary-read primitive must be treated as credential exposure.
      • Run an incident review: inspect access logs and DB entries since the server first became reachable for suspicious iclock requests; on positive hits, trigger the NIS2 incident-reporting workflow.

    2. Runbook step 2

      Mitigation layers

      • Network segmentation: place the BioTime server in a dedicated access-control VLAN; inbound traffic limited to iClock terminals on their required ports, administration only via an MFA-protected jump host.
      • WAF / reverse-proxy rule: block requests to /iclock/* containing path-traversal patterns (../, ..\\, URL-encoded %2e%2e%2f, double-encoded %252e%252e%252f, null byte %00) and typical target files (etc/passwd, web.config, wwwroot, settings.py, .env).
      • IPS/Snort/Suricata: enable generic HTTP path-traversal signatures and anchor an additional rule to the iclock URI (http.uri; content:"/iclock/").
      • Endpoint hardening: run BioTime under a dedicated low-privilege service account with tight NTFS / POSIX ACLs; make directories outside BioTime\\ unreadable to that account; deploy an AppArmor / SELinux profile for the Python or IIS worker process.
      • IAM / secret hygiene: treat all credentials present in configuration or log files as potentially leaked, rotate the DB service account, migrate secrets into a central vault.
      • Configuration: disable debug mode and directory listing; ensure error pages do not leak filesystem paths.

    3. Runbook step 3

      Detection rules

      • Web and reverse-proxy access logs: uri_path containing /iclock/ combined with ../, %2e%2e, %252e, ..%2f or %00. Sigma shape: detection: selection: cs-uri-stem|contains: '/iclock/'; cs-uri-query|contains: ['../','%2e%2e','%00'].
      • HTTP response monitoring: 200 responses to iclock requests with unusually large bodies or Content-Type text/plain / application/octet-stream instead of the expected JSON/XML.
      • Sysmon / EDR on the BioTime host: web-server processes (python.exe, w3wp.exe) reading files outside the installation directory (Sysmon EID 11 or equivalent file-access telemetry), especially web.config, *.ini, *.env, id_rsa, shadow.
      • Netflow / Zeek: non-browser user agents (curl, python-requests, empty UA) hitting the iclock endpoint from source IPs that are not approved terminals or admin hosts.
      • KQL example: W3CIISLog | where csUriStem startswith "/iclock/" and (csUriQuery has_any ("..","%2e%2e","%00") or csUriStem contains "..") | summarize count() by cIP, csUriStem.

    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 path traversal vulnerability in the iclock API of ZKTeco BioTime v8.5.5 allows unauthenticated attackers to read arbitrary files via supplying a crafted payload. This vulnerability was fixed in version 9.0.120240617.19506 of ZKBioTime.

    Source: pwn.watch, CISA KEV Catalog, NVD (NIST), cvelistv5, 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
    zktecobiotime
    • < 9.0.1
    • 9.0.1

    Vendors and products

    Weakness classes (CWE)

    • CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

      Base

      The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

      Entry at MITRE CWE-22

    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

    • zkteco.com
    • claroty.comteam82/disclosure-dashboard/cve-2023-38950
    • sploitus.comexploit?id=PACKETSTORM:177859Exploit
    • fortinet.comcontent/dam/fortinet/assets/reports/report-incident-response-mi…media-coverage
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2023-38950government-resource
    • pwn.watchpwn.watch: ZKTeco BioTime: BioTime Path Traversal Vulnerabilitypwn-watch
    • zkteco.comZKTeco advisory: ZKTeco BioTimepwn-watch
    • NVD (NIST)NVD: CVE-2023-38950pwn-watch
    • cisa.govCISA Known Exploited Vulnerabilities Catalogpwn-watch

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. NVD analysis modifiedNVD

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Reference typechanged
      CISA-ADP: https://www.fortinet.com/content/dam/fortinet/assets/reports/report-incident-response-middle-east.pdf Types: Technical Description
      CISA-ADP: https://www.fortinet.com/content/dam/fortinet/assets/reports/report-incident-response-middle-east.pdf Types: Broken Link, Technical Description

      Source identifier: nvd@nist.gov

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