External risk intelligence

TOTOLINK EX1200T Firmware Command Injection

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2021-42875

The affected product is a TOTOLINK EX1200T, which is a wireless range extender. Such devices are typically deployed as network edge infrastructure, and management interfaces on these devices are commonly accessible via the local network and, depending on configuration, can be exposed to or reachable from the internet.

OS Command Injection

Totolink Ex1200t Firmware

4.1.2cu.5215

Halo Surface Signal: 4 out of 5 — likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This vulnerability involves remote command injection in TOTOLINK EX1200T firmware, potentially allowing unauthorized control over network devices. The primary concern is to confirm if this specific technology is in use and assess any potential exposure.

Remote command execution through network devices.
Critical vulnerability requires understanding potential exposure.
Confirm if this technology is in use within the organization.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by sending specially crafted network requests to a vulnerable device. This targets a specific function responsible for network domain configuration, potentially allowing remote attackers to execute arbitrary commands on the system.

Entry: Network accessible device.
Trigger: Control of the `ipDomain` setting.
Risk: Complete system compromise.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow an unauthenticated attacker to execute arbitrary commands on the affected device by controlling the `ipDoamin` parameter. This could compromise the device's configuration and potentially its network traffic.

Device configuration and control.
Remote command execution over the network.
Unauthorized system access and manipulation.

Operational Fix

Recommended remediation, mitigation, and detection steps

This critical remote command injection vulnerability in TOTOLINK EX1200T firmware impacts network infrastructure. Network or security teams are likely responsible for managing these devices. The first step is to identify all deployed instances, assess their exposure, and determine business criticality to prioritize remediation.

Network teams should own the issue.
Verify device exposure and reachability.
Plan for coordinated remediation.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is the TOTOLINK EX1200T?

The TOTOLINK EX1200T is a wireless range extender used to expand the reach of a Wi-Fi network. It functions as a piece of networking infrastructure that bridges the gap between a primary router and remote areas where wireless coverage is weak.

What does CWE-78 mean for CVE-2021-42875?

This CVE falls under CWE-78, which is the class for OS Command Injection. It means the software does not properly filter user-supplied input before passing it to a system shell. In this case, the vulnerability allows an attacker to manipulate the 'ipDoamin' parameter to run unauthorized commands directly on the device's operating system.

How is this command injection triggered?

An attacker triggers this by sending a specially crafted network request to the device's system configuration function. This specifically targets the 'ipDoamin' parameter. Simply connecting to the device's Wi-Fi network or using standard web features without specifically interacting with this diagnostic configuration path does not trigger the vulnerability.

Why should I care about this if I use this device?

Halo Surface Signal notes that this device typically acts as network edge infrastructure. Because management interfaces on range extenders are often accessible via the local network and may be reachable from the internet depending on your configuration, a successful attack could grant an outsider complete control over your network traffic and device settings.

What are the first steps for managing this device?

You should begin by conducting an internal audit to identify if any TOTOLINK EX1200T units are currently deployed in your environment. Once identified, evaluate whether these devices are accessible from the public internet or just internal segments. Finally, work with your network administrators to determine the business role of these devices and prioritize them for security updates.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.