CVE-2018-14839
LG N1A1 NAS Remote Command Execution Vulnerability
Description
CVE-2018-14839 is a critical remote code execution vulnerability in the LG N1A1 NAS (Network Attached Storage) device that allows unauthenticated attackers to execute arbitrary commands on the underlying operating system via command injection. The vulnerability exists because the device fails to properly validate user-supplied input in its web management interface, enabling injection of OS commands without any authentication. CISA has added CVE-2018-14839 to the Known Exploited Vulnerabilities catalog due to confirmed active exploitation. With an EPSS score of 90.3% (98.5th percentile), this vulnerability represents a severe threat to any environment running exposed LG N1A1 NAS devices.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| lg | n1a1 firmware | 3718.510 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://medium.com/%400x616163/lg-n1a1-unauthenticated-remote-command-injection-cve-2018-14839-9d2cf760e247(Exploit, Third Party Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-14839(US Government Resource)
Weakness Type
CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CWE-78 describes a weakness where software constructs operating system commands using externally-influenced input without properly neutralizing special elements that could modify the intended command. In CVE-2018-14839, the LG N1A1 NAS device's web interface passes user input directly into system commands without adequate sanitization, allowing an unauthenticated remote attacker to inject and execute arbitrary OS commands.
Learn more: CWE-78 — OS Command Injection
Impact Analysis
CVE-2018-14839 enables unauthenticated remote command execution on LG N1A1 NAS devices, granting attackers full control over the device and all data stored on it. NAS devices commonly hold sensitive business documents, personal files, backup data, and shared resources, making a successful compromise extremely damaging from a confidentiality perspective. Attackers can read, modify, or encrypt all stored files, install persistent backdoors, and use the compromised device as a launching point for attacks against other systems on the local network. The unauthenticated nature of the exploit means any attacker with network access to the device can immediately achieve full system compromise. The EPSS score of 90.3% (98.5th percentile) confirms widespread and active exploitation of this vulnerability.
Exploit Maturity
CVE-2018-14839 is actively exploited in the wild, as confirmed by its inclusion in the CISA Known Exploited Vulnerabilities catalog. The exploit is straightforward, requiring only an unauthenticated HTTP request to the web management interface, making it easily automated by botnets and mass scanning tools. The EPSS score of 90.3% (98.5th percentile) reflects very high exploitation probability. Consumer and small-business NAS devices like the LG N1A1 are frequently targeted by ransomware operators and cryptomining malware due to their limited security features and common internet exposure.
Remediation
- Apply firmware updates from LG if available for the N1A1 NAS device. If no patch is available or the device has reached end-of-life, disconnect it from the network and replace it with a supported, actively maintained NAS solution.
- Immediately ensure the LG N1A1 NAS device is not accessible from the internet by disabling port forwarding, UPnP, and any remote access features that expose the web management interface.
- Place the NAS device on an isolated network segment accessible only from trusted internal systems, using firewall rules to restrict all direct access from untrusted networks.
- Audit all data stored on the NAS for signs of tampering, unauthorized access, or encryption that may indicate prior exploitation or ransomware activity.
- Change all credentials stored on or accessible through the NAS device, and implement monitoring on the network segment to detect any anomalous activity from the NAS device.
Technical Details
CVE-2018-14839 is an OS command injection vulnerability (CWE-78) in the web management interface of the LG N1A1 NAS device. The vulnerability exists because user-supplied input is incorporated into operating system commands without proper validation or escaping of shell metacharacters. An unauthenticated remote attacker can exploit this flaw by sending a crafted HTTP request containing command injection payloads to the web interface, resulting in execution of arbitrary commands on the underlying Linux operating system with the privileges of the web server process. The lack of authentication requirement means the vulnerability can be exploited by any network-connected attacker, and the simple HTTP-based attack vector makes it trivially automatable. LG N1A1 NAS devices are consumer-grade storage appliances with limited security hardening, making them particularly susceptible to this class of vulnerability.
Frequently Asked Questions
Is CVE-2018-14839 being actively exploited?
Yes, CVE-2018-14839 is actively exploited in the wild and is listed in the CISA Known Exploited Vulnerabilities catalog. The EPSS score of 90.3% (98.5th percentile) confirms very high exploitation activity. Consumer NAS devices are frequent targets for ransomware and cryptomining botnets.
What products are affected by CVE-2018-14839?
CVE-2018-14839 affects the LG N1A1 NAS (Network Attached Storage) device. The vulnerability is in the web management interface that provides administrative access to the NAS device.
How do I fix CVE-2018-14839?
Apply any available firmware updates from LG for the N1A1 NAS. If no update is available, the device should be disconnected from the internet and ideally replaced with a supported NAS product. At minimum, ensure the device is not exposed to the public internet and restrict access to trusted internal networks only.
How severe is CVE-2018-14839?
CVE-2018-14839 is rated CRITICAL as it enables unauthenticated remote command execution on the NAS device. The EPSS score of 90.3% (98.5th percentile) indicates very high exploitation probability. Any LG N1A1 NAS exposed to the network without mitigation should be considered at immediate risk of compromise.
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