CVE-2018-6530
D-Link Multiple Routers OS Command Injection Vulnerability
Description
CVE-2018-6530 is an OS command injection vulnerability affecting multiple D-Link router models that allows remote attackers to execute arbitrary operating system commands on the device. The vulnerability exists due to insufficient input sanitization in the web management interface, enabling unauthenticated command execution. This is a particularly severe flaw because D-Link routers are commonly deployed in both consumer and small business environments, and compromised routers can serve as entry points for broader network attacks. CISA has added CVE-2018-6530 to its Known Exploited Vulnerabilities catalog, with the vulnerability being associated with known ransomware campaigns. The EPSS score of 94.3% (99th percentile) reflects near-certain exploitation activity.
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 |
|---|---|---|
| dlink | dir-860l firmware | <= 1.10b04 |
| dlink | dir-865l firmware | <= 1.08b01 |
| dlink | dir-868l firmware | <= 1.12b04 |
| dlink | dir-880l firmware | <= 1.08b04 |
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
- ftp://FTP2.DLINK.COM/SECURITY_ADVISEMENTS/DIR-860L/REVA/DIR-860L_REVA_FIRMWARE_PATCH_NOTES_1.11B01_EN_WW.pdf(Release Notes, Vendor Advisory)
- ftp://FTP2.DLINK.COM/SECURITY_ADVISEMENTS/DIR-868L/REVA/DIR-868L_REVA_FIRMWARE_PATCH_NOTES_1.20B01_EN_WW.pdf(Release Notes, Vendor Advisory)
- ftp://ftp2.dlink.com/SECURITY_ADVISEMENTS/DIR-865L/REVA/DIR-865L_REVA_FIRMWARE_PATCH_NOTES_1.10B01_EN_WW.pdf(Release Notes, Vendor Advisory)
- ftp://ftp2.dlink.com/SECURITY_ADVISEMENTS/DIR-880L/REVA/DIR-880L_REVA_FIRMWARE_PATCH_NOTES_1.08B06_EN_WW.pdf(Release Notes, Vendor Advisory)
- https://github.com/TheBeeMan/Pwning-multiple-dlink-router-via-SOAP-proto(Exploit, Third Party Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-6530(US Government Resource)
Weakness Type
CWE-78: OS Command Injection
CVE-2018-6530 exploits an OS command injection weakness in multiple D-Link routers, where external input is incorporated into operating system commands without proper neutralization of special characters. The web management interface of the affected routers fails to sanitize user-supplied parameters, allowing an attacker to inject shell metacharacters that are executed as part of the system command, achieving arbitrary command execution with the privileges of the web server process.
Learn more: CWE-78 — Improper Neutralization of Special Elements used in an OS Command
Impact Analysis
CVE-2018-6530 represents a critical threat to network perimeter security. The vulnerability is remotely exploitable over the network without authentication, requiring no user interaction and involving low attack complexity. Successful exploitation grants the attacker the ability to execute arbitrary OS commands on the router, which can lead to complete device takeover, modification of network routing and DNS settings, interception of all network traffic passing through the device, and deployment of persistent malware. The confirmed association with ransomware campaigns significantly elevates the business risk, as compromised routers can be used to facilitate ransomware deployment across connected networks. With an EPSS score of 94.3% (99th percentile), this vulnerability is among the most actively targeted across all known CVEs, and the fact that many affected D-Link models have reached end-of-life makes remediation particularly challenging.
Exploit Maturity
CISA has confirmed active exploitation of CVE-2018-6530 in the wild and has specifically flagged it as being used in ransomware campaigns. The EPSS score of 94.3% (99th percentile) indicates near-certain exploitation activity, reflecting both the availability of public exploit code and the widespread deployment of vulnerable D-Link routers. The vulnerability is trivially exploitable by sending crafted HTTP requests to the router's web interface, and exploit scripts are widely available in the security community. D-Link published an advisory noting that the fix under CVE-2018-20114 properly patches this vulnerability, but many affected models have reached end-of-life and will not receive updates.
Remediation
- Apply the vendor patch or disconnect end-of-life devices: Per the CISA KEV required action, if the device is still supported, apply the fix referenced under CVE-2018-20114 per D-Link's advisory (SAP10105). If the affected device has entered end-of-life, it should be disconnected and replaced immediately.
- Replace end-of-life D-Link routers: Since many affected models no longer receive security updates, replace them with currently supported network equipment from any vendor that provides ongoing security patches.
- Disable remote management interfaces: If the router must remain in service temporarily, disable the web management interface from WAN-facing interfaces to prevent remote exploitation. Only allow management access from trusted internal network segments.
- Implement network-level protection: Place affected routers behind a firewall that can filter malicious HTTP requests, and deploy IDS/IPS rules to detect OS command injection attempts targeting D-Link router management interfaces.
- Monitor for indicators of compromise: Check connected networks for signs of unauthorized access, unexpected DNS configuration changes, or traffic anomalies that could indicate the router has been compromised and is being used as a pivot point for ransomware deployment.
Technical Details
CVE-2018-6530 is an OS command injection vulnerability in the web management interface of multiple D-Link router models. The vulnerability exists in the handling of HTTP request parameters, where user-supplied input is passed directly to operating system command execution functions (such as system() or popen()) without proper sanitization of shell metacharacters. An attacker can inject arbitrary commands by including characters such as semicolons, pipes, or backticks in the request parameters, which are then interpreted by the system shell. The attack requires no authentication as the vulnerable endpoint is accessible before any login process, making it exploitable by any attacker who can reach the router's web interface. The fix referenced under CVE-2018-20114 addresses this by implementing proper input validation and command parameterization to prevent shell metacharacter injection.
Frequently Asked Questions
Is CVE-2018-6530 being actively exploited?
Yes. CISA has confirmed active exploitation of CVE-2018-6530 and has specifically identified it as being used in ransomware campaigns. With an EPSS score of 94.3% (99th percentile), exploitation is near-certain for any exposed vulnerable device. Immediate action is required.
What products are affected by CVE-2018-6530?
CVE-2018-6530 affects multiple D-Link router models. Many of the affected models have reached end-of-life and will no longer receive security updates from D-Link. The specific affected models are listed in D-Link's security advisory SAP10105.
How do I fix CVE-2018-6530?
For supported D-Link routers, apply the patch referenced under CVE-2018-20114 per D-Link's advisory. For end-of-life devices, CISA recommends disconnecting them from the network and replacing them with currently supported hardware. As an interim measure, disable remote management access.
How severe is CVE-2018-6530?
CVE-2018-6530 is a critical severity OS command injection vulnerability that allows unauthenticated remote command execution. Its EPSS score of 94.3% (99th percentile) and confirmed use in ransomware campaigns make it one of the highest-risk vulnerabilities for exposed network devices. Organizations should treat remediation as an emergency priority.
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