MediumCVE-2020-27403

    TCL 32s330 Firmware: Information Disclosure (CVE-2020-27403)

    Published Sources: CVE.org

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    What is affected, what to do

    A vulnerability in the TCL Android Smart TV series V8-R851T02-LF1 V295 and below and V8-T658T01-LF1 V373 and below by TCL Technology Group Corporation allows an attacker on the adjacent network to arbitrarily browse and download sensitive files over an insecure web server running on port 7989 that lists all files & directories. An unprivileged remote attacker on the adjacent network, can download most system files, leading to serious critical information disclosure.

    An exploit is publicly available. Update TCL 32s330 Firmware to version v8-r851t10-lf1v091, TCL 40s330 Firmware to version v8-r851t10-lf1v091, TCL 43s434 Firmware to version v8-r851t02-lf1v440.

    Affected
    • TCL 32s330 Firmware lt *..v8-r851t10-lf1v091
    • TCL 40s330 Firmware lt *..v8-r851t10-lf1v091
    • TCL 43s434 Firmware lt *..v8-r851t02-lf1v440
    • TCL 50s434 Firmware lt *..v8-r851t02-lf1v440
    • TCL 55s434 Firmware lt *..v8-r851t02-lf1v440
    • TCL 65s434 Firmware lt *..v8-r851t02-lf1v440
    • TCL 75s434 Firmware lt *..v8-r851t02-lf1v440
    Fixed in
    • TCL 32s330 Firmware v8-r851t10-lf1v091
    • TCL 40s330 Firmware v8-r851t10-lf1v091
    • TCL 43s434 Firmware v8-r851t02-lf1v440
    • TCL 50s434 Firmware v8-r851t02-lf1v440
    • TCL 55s434 Firmware v8-r851t02-lf1v440
    • TCL 65s434 Firmware v8-r851t02-lf1v440
    • TCL 75s434 Firmware v8-r851t02-lf1v440

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

    Metrics

    6.5

    Priority

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

    Source: NVD, CVSS v3

    6.5

    CVSS v3

    Severity Medium on the scale from 0 to 10.

    Source: CVE.org

    2.7 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 86.0

    Show all metrics
    Severity
    Medium
    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
    91.71 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
    PoC (publicly reported)
    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
    6.5 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
    6.5
    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
    2.7 %
    Moderate — model estimates 1-10% 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
    86.0
    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
    —
    Published

    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
    Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
    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
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    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 vulnerability in the TCL Android Smart TV series V8-R851T02-LF1 V295 and below and V8-T658T01-LF1 V373 and below by TCL Technology Group Corporation allows an attacker on the adjacent network to arbitrarily browse and download sensitive files over an insecure web server running on port 7989 that lists all files & directories. An unprivileged remote attacker on the adjacent network, can download most system files, leading to serious critical information disclosure. Also, some TV models and/or FW versions may expose the webserver with the entire filesystem accessible on another port. For example, nmap scan for all ports run directly from the TV model U43P6046 (Android 8.0) showed port 7983 not mentioned in the original CVE description, but containing the same directory listing of the entire filesystem. This webserver is bound (at least) to localhost interface and accessible freely to all unprivileged installed apps on the Android such as a regular web browser. Any app can therefore read any files of any other apps including Android system settings including sensitive data such as saved passwords, private keys etc.

    Source: NVD (NIST), cvelistv5

    Vendors and products

    Affected operating systems

    Affected operating systems
    Othertcl32s330_firmware—
    Othertcl40s330_firmware—
    Othertcl43s434_firmware—
    Othertcl50s434_firmware—
    Othertcl55s434_firmware—
    Othertcl65s434_firmware—
    Othertcl75s434_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
    Reference tagged as exploitgithub.com (opens in a new tab)PoC (publicly reported)reported, not verified—

    References & sources

    • github.comsickcodesx_refsource_MISC, Third-party advisory
    • github.comsickcodes/security/blob/master/advisories/SICK-2020-009.mdx_refsource_MISC, Exploit, Third-party advisory
    • sick.codessick-2020-009x_refsource_MISC, Exploit, Third-party advisory
    • sick.codesextraordinary-vulnerabilities-discovered-in-tcl-android-tvs-now…x_refsource_MISC, Exploit, Third-party advisory
    • github.comsickcodes/security/issues/1x_refsource_MISC, Third-party advisory
    • github.comsickcodes/security/blob/master/etc/CVE-2020-27403_CVE-2020-2805…x_refsource_MISC, Third-party advisory
    • github.comsickcodes/security/blob/master/etc/CVE-2020-27403_CVE-2020-2805…x_refsource_MISC, Third-party advisory
    • securityledger.com2020/11/security-holes-opened-back-door-to-tcl-android-smart-tvsx_refsource_MISC, Third-party advisory
    • securityledger.com2020/11/tv-maker-tcl-denies-back-door-promises-better-processx_refsource_MISC, Third-party advisory
    • support.tcl.comvulnerabilities-found-in-tcl-android-tvsx_refsource_MISC, Vendor advisory
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