CriticalCVE-2018-10562

    Dasan GPON Routers Command Injection Vulnerability (CVE-2018-10562)

    Published In CISA KEV since Sources: CVE.org

    What is affected, what to do

    Dasan GPON routers have an authentication bypass vulnerability that, when combined with CVE-2018-10561, allows an attacker to perform remote code execution (RCE). This vulnerability can be exploited remotely, granting the attacker full control over the device. It is actively exploited in ransomware campaigns since 2022. All versions of dasannetworks/gpon_router_firmware are affected. Immediate updating to the latest firmware version is critical to mitigate this risk.

    The vulnerability is being actively exploited; treat it as a priority. CISA lists it as used in ransomware campaigns. 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.

    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: CVE.org

    99.95 %

    EPSS score

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

    Source: FIRST EPSS, percentile 99.97

    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
    253.95 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.

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    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.

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    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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    99.95 %
    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.

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    99.97
    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.

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    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

    Response and mitigation

    Why act now?

    Prioritisation rationale

    The flaw has been weaponised at scale since 2018 by IoT botnet families (Mirai derivatives, Muhstik, TheMoon) and sits on KEV because mass, fully automated exploitation requires no authentication and no user interaction — exploitation likelihood is among the very highest tracked. CISA flags ransomware use, so compromised GPON devices also serve as a pivot into downstream customer or branch networks. For NIS2-regulated operators the priority is high wherever your own branches, service depots or KRITIS sites still use Dasan GPON ONTs with WAN-exposed management; for consumer-ISP routers at employees' home offices, enforce always-on VPN rather than patching, as the device is not under your administration.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Inventory all Dasan GPON routers (ISP-provisioned ONTs, branch-office CPEs) via DHCP fingerprints, SNMP sysDescr and HTTP banners carrying GponForm/ paths; treat any match as potentially compromised.
      • Block the management plane from the WAN side immediately — perimeter ACL "deny any to port 80, 443, 7547" and, where CLI access exists, disable WAN-side HTTP(S) and TR-069 on the CPE itself.
      • No reliable vendor patch exists for the affected GPON firmware branches and many units are end-of-support: initiate a replacement plan. As an interim, force affected devices into an isolated VLAN with no routing to internal networks.
      • Any device that was reachable from the internet on /GponForm/diag_Form or /diag.html must be assumed compromised: factory reset, reflash to the latest firmware the vendor still publishes, then rotate credentials (admin, PPPoE, WLAN PSK, TR-069 ACS secret).
      • IOC sweep for known botnet families abusing this flaw (Mirai variants, Muhstik, Hajime, Satori derivatives): outbound connections to typical IRC/C2 ports (TCP/23, TCP/2323, TCP/6667, TCP/1024-1026) and LAN scanning behaviour from CPE segments.

    2. Runbook step 2

      Mitigation layers

      • Network segmentation: place GPON CPEs in a dedicated management VLAN; only the ACS/TR-069 server and NMS may initiate traffic, no east-west reachability into office or OT networks.
      • WAF/reverse proxy in front of any exposed device: block requests containing diag_action=ping combined with shell metacharacters (;, |, `, $(, &&) in the dest_host parameter; restrict methods to GET/POST, drop everything else.
      • Enable IPS signatures for CVE-2018-10561/10562 (ET Open SIDs 2025717, 2025718 and follow-ups); alert on any GponForm/diag_Form URI with payload inspection enabled.
      • Egress filtering on the CPE subnet: outbound default-deny; permit only DNS (UDP/53), NTP (UDP/123) and HTTP(S) to known update endpoints; rate-limit SYN scans and block outbound TCP/23 and TCP/2323.
      • If replacement is not immediate: front the management UI with a reverse proxy enforcing mTLS; where root shell is available, bind the native web server to loopback via iptables.
      • Monitor TR-069 configuration: unexpected changes to ACS URL or firmware URL are a high-severity event — attackers use TR-069 to establish persistence after initial RCE.

    3. Runbook step 3

      Detection rules

      • Zeek/Suricata HTTP log: uri contains GponForm/diag_Form AND query or POST body contains diag_action=ping AND dest_host= includes non-IP characters (;, |, `, %3B, %7C). Sigma shape: detection: selection: cs-uri-stem|contains: '/GponForm/diag_Form' cs-uri-query|re: '(?i)dest_host=[^&]*[;| + "" + $()]'`.
      • Perimeter load-balancer access log: GET on /diag.html within 5 seconds of a POST on /GponForm/diag_Form from the same source IP — this is the command-output retrieval pattern.
      • Netflow/Zeek conn.log: GPON CPEs originating outbound connections to known Mirai-loader behaviours (scanning TCP/23, TCP/2323, TCP/5555, TCP/37215, TCP/52869) or pulling ELF binaries via wget/tftp from the CPE segment.
      • DNS telemetry: CPE clients resolving DGA-style domains or known botnet C2 hostnames; correlate with HTTP User-Agent Hello, World or empty User-Agent values.
      • KQL (when network telemetry is available in Sentinel): CommonSecurityLog | where RequestURL contains "GponForm/diag_Form" or RequestURL contains "diag.html" | where RequestClientApplication == "" or Message contains "dest_host=".

    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

    An issue was discovered on Dasan GPON home routers. Command Injection can occur via the dest_host parameter in a diag_action=ping request to a GponForm/diag_Form URI. Because the router saves ping results in /tmp and transmits them to the user when the user revisits /diag.html, it's quite simple to execute commands and retrieve their output.

    Source: NVD (NIST), cvelistv5, CISA KEV Catalog

    Vendors and products

    Affected operating systems

    Affected operating systems
    Otherdasannetworksgpon_router_firmware—

    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
    Exploit-DBEDB-ID 44576 (opens in a new tab)exploit-db.comPoC (publicly reported)reported, not verified—

    References & sources

    • securityfocus.com107053Vulnerability database, x_refsource_BID, Broken link, Third-party advisory, Vulnerability database
    • exploit-db.com44576Exploit, x_refsource_EXPLOIT-DB, Exploit, Third-party advisory, Vulnerability database
    • vpnmentor.comblog/critical-vulnerability-gpon-routerx_refsource_MISC, Exploit, Technical description, Third-party advisory
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2018-10562government-resource, US government resource
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