CriticalCVE-2022-24990

    TerraMaster OS Remote Command Execution Vulnerability (CVE-2022-24990)

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

    What is affected, what to do

    TerraMaster NAS 4.2.29 and earlier allows remote attackers to discover the administrative password by sending "User-Agent: TNAS" to module/api.php?mobile/webNasIPS and then reading the PWD field in the response.

    The vulnerability is being actively exploited; treat it as a priority. CISA lists it as used in ransomware campaigns. Update TerraMaster Operating System TOS to version 4.2.31. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • TerraMaster Operating System TOS lt *..4.2.31
    Fixed in
    • TerraMaster Operating System TOS 4.2.31

    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: Vendor (CNA), CVSS v3

    7.5

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: pwn.watch, CVE.org

    83.2 %

    EPSS score

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

    Source: FIRST EPSS, percentile 99.68

    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
    244.13 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
    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
    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“.

    Read in glossary
    83.2 %
    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
    99.68
    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 22 December 2023
    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-306

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This CVE sits on KEV because the pre-auth credential leak reliably chains into remote command execution, and CISA has flagged it with "known ransomware campaign use" — affected TOS appliances are a confirmed encryption target, not a theoretical risk. The vector is network-reachable without authentication, public exploit tooling is widely available, and its exploitation likelihood ranks among the highest on the KEV list. Treat any TOS instance exposed to the internet, directly or via port forward, as P1 and take it offline within 24 hours without exception. Internal-only appliances are P2 but belong in the same patch cycle, since mid-market and KRITIS environments regularly see lateral movement from compromised endpoints pivot onto NAS systems as the primary ransomware payload target.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Upgrade TerraMaster OS (TOS) to 4.2.33 or newer — the fix closes both the pre-auth information disclosure via module/api.php?mobile/webNasIPS and the follow-on RCE chain. Confirm the exact patched build in the vendor advisory, especially on appliances that have missed several update cycles.
      • Until patched: take TNAS devices off the public internet entirely. Perimeter firewall: DROP inbound TCP/5443, TCP/8181, TCP/80, TCP/443 to any TOS appliance. Actively delete router/UTM port forwards; disabling is not enough.
      • Rotate every local TOS account including admin, since the pre-auth leak exposes the password hash. Block web-UI access before rotating, otherwise the new credential is harvested as soon as it is set.
      • Inspect running processes via SSH: kill any unexpected sh, python, wget, curl, nc or reverse shells running as root or www-data, and flag the host as potentially compromised. Snapshot the current state for forensics before any rebuild.
      • Restrict administrative access to VPN plus jump host; keep the TNAS web interface off the public internet as a permanent policy, not a transitional measure.

    2. Runbook step 2

      Mitigation layers

      • Network segmentation: place TOS appliances in a dedicated storage VLAN, allow access only from defined backup and file-server subnets, and whitelist outbound traffic via an egress proxy. The NAS itself must not reach the public internet directly — this blocks C2 after a successful RCE.
      • WAF/reverse proxy in front of TOS (nginx, HAProxy, Traefik): block external requests to module/api.php with query mobile/webNasIPS or header User-Agent: TNAS. Example Snort/Suricata pattern: alert http any any -> $TOS_NET any (msg:"TerraMaster TOS CVE-2022-24990 preauth info leak"; http.uri; content:"module/api.php"; content:"webNasIPS"; http.user_agent; content:"TNAS"; sid:1002224990;).
      • IAM hardening: enable two-factor authentication inside TOS, rename the admin account, and use dedicated service accounts for SMB/NFS shares rather than the admin login.
      • Configuration: disable SSH on TOS if not operationally required; if needed, enforce key-based auth and PermitRootLogin no. Uninstall unused apps (Plex, Docker containers, phpMyAdmin) to shrink the lateral-movement surface.
      • Backup posture: deploy immutable or offline backups, because TOS appliances are an active ransomware encryption target. Keep at least 14 days of snapshots outside the NAS itself — not on the same device.

    3. Runbook step 3

      Detection rules

      • Access logs (nginx/Apache in front of TOS, or TOS access logs directly): look for GET /module/api.php?mobile/webNasIPS with User-Agent: TNAS from external or unexpected source IPs. KQL shape: WebLogs | where UriQuery has "webNasIPS" and UserAgent has "TNAS" and SrcIp !in (allowed_mgmt_ips).
      • Zeek http.log / Suricata eve.json: short bursts of several api.php requests within seconds, followed by a POST to the login endpoint from the same source, indicate a credential-chain exploit in progress.
      • Process telemetry on the NAS (via EDR, osquery or auditd): web-server process (php-fpm, httpd) as parent of sh, bash, wget, curl, nc or python. Sigma shape: parent_image endswith 'php-fpm' and image in ('/bin/sh','/usr/bin/wget','/usr/bin/curl','/bin/nc').
      • Network egress: outbound connections from the TOS management IP to anything other than vendor update endpoints (e.g. update.terra-master.com), especially to known ransomware C2 infrastructure or Tor exit nodes. Alert on deny events for atypical destinations.
      • Filesystem: new or modified files in /usr/local/www/, /root/, cron entries under /etc/cron.*, and changes to SSH authorized_keys. Auditd watch rule: -w /root/.ssh/authorized_keys -p wa -k ssh_persist.

    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

    TerraMaster NAS 4.2.29 and earlier allows remote attackers to discover the administrative password by sending "User-Agent: TNAS" to module/api.php?mobile/webNasIPS and then reading the PWD field in the response.

    Source: pwn.watch, NVD (NIST), cvelistv5, CISA KEV Catalog, CVE.org (MITRE)

    Vendors and products

    Affected operating systems

    Affected operating systems
    Otherterra-masterterramaster_operating_system—

    Weakness classes (CWE)

    • CWE-306Missing Authentication for Critical Function

      Base

      The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

      Entry at MITRE CWE-306

    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
    GitHub0xf4n9x/CVE-2022-24990 (opens in a new tab)github.comPoC (publicly reported)reported, not verified—
    Packet StormTerraMaster TOS 4.2.29 Remote Code Execution (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—

    References & sources

    • forum.terra-master.comen/viewforum.php?f=28Issue tracking, Release notes
    • broadcom.comsupport/security-center/attacksignatures/detail?asid=33732Third-party advisory
    • github.com0xf4n9x/CVE-2022-24990Exploit, Third-party advisory
    • octagon.netblog/2022/03/07/cve-2022-24990-terrmaster-tos-unauthenticated-r…Exploit, Third-party advisory
    • packetstormsecurity.comfiles/172904/TerraMaster-TOS-4.2.29-Remote-Code-Execution.htmlExploit, Third-party advisory, Vulnerability database
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2022-24990government-resource, US government resource
    • pwn.watchpwn.watch: TerraMaster OS: Remote Command Execution (CVE-2022-24990)pwn-watch
    • forum.terra-master.comVendor advisory: TerraMaster OSpwn-watch
    • NVD (NIST)NVD: CVE-2022-24990pwn-watch
    • cisa.govCISA Known Exploited Vulnerabilities Catalogpwn-watch
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