CriticalCVE-2014-3120

    Elasticsearch Remote Code Execution Vulnerability (CVE-2014-3120)

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

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    What is affected, what to do

    The default configuration in Elasticsearch before 1.2 enables dynamic scripting, which allows remote attackers to execute arbitrary MVEL expressions and Java code via the source parameter to _search. NOTE: this only violates the vendor's intended security policy if the user does not run Elasticsearch in its own independent virtual machine.

    The vulnerability is being actively exploited; treat it as a priority. Update Elasticsearch to version 1.2.0. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Elasticsearch lt *..1.2.0
    Fixed in
    • Elasticsearch 1.2.0

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

    Metrics

    8.1

    Priority

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

    Source: NVD, CVSS v3

    8.1

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: CVE.org, OSV

    88.6 %

    EPSS score

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

    Source: FIRST EPSS, percentile 99.77

    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
    220.13 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
    8.1 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
    8.1
    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
    88.6 %
    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
    99.77
    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: partial
    Source: CISA Vulnrichment, as of 10 February 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 CVE is on KEV because unpatched Elasticsearch nodes have been systematically abused for years for RCE, cryptomining (Bondnet, Mirai variants) and data theft; it is network-reachable, needs essentially no authentication in default deployments, and its exploitation likelihood ranks among the very highest across the entire CVE corpus. The real exposure is rarely the actively maintained ES cluster — it hides in forgotten dev/test instances, legacy ETL pipelines and unmaintained container images. Treat as P1 whenever any node is below 1.2 or has script.disable_dynamic unset and is reachable from anything less than a fully trusted segment; even in purely internal exposure keep it at P2, because lateral movement from a compromised app server is a realistic path.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Inventory every Elasticsearch node (ports 9200/9300, including container, dev and shadow-IT instances) and identify versions below 1.2.0. Plan the upgrade; 1.x is long end-of-life, so the real target is a currently supported 7.x/8.x line.
      • Disable dynamic scripting immediately: set script.disable_dynamic: true in elasticsearch.yml and restart the node. This is the vendor's official short-term mitigation and neutralises the exploit path.
      • Block ports 9200 (HTTP) and 9300 (transport) at the perimeter and between internal segments. Elasticsearch must never be directly reachable from the internet or from user VLANs. If external access is required, put an authenticating reverse proxy in front.
      • Forensically triage every exposed node (see detection rules). On any hit: isolate the host, snapshot it, rotate every credential/token reachable from the host, and open an incident ticket.
      • Run the Elasticsearch process as a dedicated unprivileged user (never root) and harden the systemd unit with NoNewPrivileges=yes, ProtectSystem=strict to limit post-exploitation blast radius.

    2. Runbook step 2

      Mitigation layers

      • Network segmentation: place ES nodes in a dedicated backend VLAN, allow ingress on 9200/9300 only from defined application servers via firewall ACL. No default-allow from management or developer networks.
      • Reverse proxy (nginx, HAProxy, or Elastic's own security features in modern versions): enforce authentication, apply rate limiting, and block _search requests whose body contains script, script_fields or MVEL/Groovy keywords (java.lang, Runtime, getRuntime, exec).
      • WAF/IPS rule: inspect bodies posted to /_search, /*/_search, /_msearch for suspicious patterns ("script"\s*:, "lang"\s*:\s*"(mvel|groovy|javascript)", Runtime.getRuntime). ET Open ships Snort/Suricata signatures for CVE-2014-3120.
      • Host hardening: run Elasticsearch inside its own VM or container with an SELinux/AppArmor profile, and restrict egress from the ES user via iptables/nftables to a strict allow-list — this breaks reverse shells and crypto-miner payload fetches.
      • IAM / least privilege: the ES service account should have no shell, no sudo, and no write access outside data and log directories. This prevents persistence via cron, systemd timers, or ~/.ssh/authorized_keys drops.
      • Enable the slow log and audit log for _search requests and forward them to the SIEM.

    3. Runbook step 3

      Detection rules

      • Web-server / proxy logs: POST or GET to /_search or /*/_search with bodies containing script, mvel, java.lang.Runtime, getRuntime(), exec(, java.io.BufferedReader. KQL shape: url.path:*_search* and (http.request.body.content:*Runtime.getRuntime* or http.request.body.content:*java.lang.Math*).
      • Process telemetry (Sysmon EID 1 / auditd execve): any child of the Elasticsearch Java process that is not java — especially sh, bash, curl, wget, python, perl, nc, chmod +x. Sigma shape: parent_image endswith 'java' and parent_command_line contains 'elasticsearch' and image in (sh,bash,curl,wget,python,perl,nc).
      • Network (Zeek/Suricata): outbound connections from the ES host to non-whitelisted IPs, especially on 4444, 1337, 8080, or to known mining-pool domains (e.g. *.pool.minexmr.com).
      • Filesystem: new executable files under /tmp, /var/tmp, /dev/shm owned by the ES user. Auditd rule: -w /tmp -p wa -k es_rce.
      • Elasticsearch audit / slow log: _search requests containing script_fields or with body size above roughly 2 KB on indices that normally see short queries — high false-positive rate without a baseline, so always correlate with process telemetry.

    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

    The default configuration in Elasticsearch before 1.2 enables dynamic scripting, which allows remote attackers to execute arbitrary MVEL expressions and Java code via the source parameter to _search. NOTE: this only violates the vendor's intended security policy if the user does not run Elasticsearch in its own independent virtual machine.

    Source: NVD (NIST), OSV (Open Source Vulnerabilities), 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
    elasticelasticsearch
    • < 1.2.0
    • 1.2.0
    mavenorg.elasticsearch:elasticsearch
    • 0.18.7
    • 1.0.0.RC1
    • 1.2.0
    • 0.90.3
    • 0.19.5
    • 0.19.0
    • 0.17.2
    • 0.8.0
    • 0.17.6
    • 0.90.0.Beta1
    • 0.19.12
    • 0.18.4
    • 0.17.8
    • 0.16.4
    • 0.15.0
    • 1.3.3
    • 0.19.1
    • 0.20.4
    • 0.14.4
    • 0.20.1
    • 0.90.12
    • 1.1.0
    • 0.19.9
    • 1.3.2
    • 0.18.6
    • 1.0.1
    • 0.15.1
    • 1.0.0.Beta2
    • 0.13.0
    • 0.11.0
    • 0.90.10
    • 0.7.1
    • 0.6.0
    • 0.19.3
    • 1.3.7
    • 0.19.7
    • 0.19.0.RC3
    • 0.15.2
    • 0.16.1
    • 0.90.9
    • 1.2.4
    • 1.1.2
    • 1.3.6
    • 0.16.0
    • 0.12.0
    • 1.0.0.RC2
    • 1.3.1
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    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
    Metasploit FrameworkMetasploit: exploit/multi/elasticsearch/script_mvel_rce (opens in a new tab)rapid7.comweaponized (Metasploit module)reported, not verified—
    Exploit-DBEDB-ID 33370 (opens in a new tab)exploit-db.comPoC (publicly reported)reported, not verified—
    PoC-in-GitHub (nomi-sec)vulhub-elasticsearch-cve-2014-3120 (opens in a new tab)github.comPoC (publicly reported)reported, not verified

    References & sources

    • NVD (NIST)vuln/detail/CVE-2014-3120advisory
    • github.comelastic/elasticsearch/issues/7151web
    • github.comelastic/elasticsearch/pull/7642web
    • github.comelastic/elasticsearch/commit/bd0eb32d9c3c3f5b6e5f8630c859cd04bd…web
    • github.comelastic/elasticsearch/commit/f9de8b65898509e038e33215db0720b508…web
    • github.comelastic/elasticsearchpackage
    • web.archive.orgweb/20140813071419/http://www.securityfocus.com/bid/67731web
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2014-3120web, government-resource, US government resource
    • elastic.coblog/logstash-1-4-3-releasedweb, x_refsource_CONFIRM, Vendor advisory
    • elastic.cocommunity/securityweb
    • found.nofoundation/elasticsearch-securityweb, x_refsource_MISC, Exploit
    • bouk.coblog/elasticsearch-rceweb
    • exploit-db.com33370web, Exploit, x_refsource_EXPLOIT-DB, Exploit
    • rapid7.comdb/modules/exploit/multi/elasticsearch/script_mvel_rceweb, x_refsource_MISC, Exploit, Third-party advisory
    • securityfocus.com67731Vulnerability database, x_refsource_BID, Exploit
    • osvdb.org106949Vulnerability database, x_refsource_OSVDB, Broken link
    • bouk.coblog/elasticsearch-rcex_refsource_MISC, Exploit
    • elastic.cocommunity/securityx_refsource_CONFIRM, Vendor advisory
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