CVE-2024-21786: MC LR Router Firmware RCE Vulnerability

CVE-2024-21786 Overview

CVE-2024-21786 is an operating system (OS) command injection vulnerability in the MC Technologies MC LR Router firmware version 2.10.5. The flaw resides in the configuration upload functionality of the router's web interface. An authenticated attacker can send a specially crafted HTTP request to execute arbitrary commands on the underlying operating system. The vulnerability is tracked under CWE-78 and was reported by Cisco Talos as advisory TALOS-2024-1954. Successful exploitation gives attackers full control over the router, exposing the device and connected network segments to further compromise.

Critical Impact
Authenticated attackers can achieve arbitrary command execution on the router, leading to full device compromise and potential pivoting into internal networks.

Affected Products

MC Technologies MC LR Router (hardware)
MC Technologies MC LR Router Firmware version 2.10.5
Deployments exposing the router's web configuration interface to reachable networks

Discovery Timeline

2024-11-21 - CVE-2024-21786 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-21786

Vulnerability Analysis

The vulnerability exists in the configuration upload feature of the MC LR Router web administration interface. The upload handler processes user-supplied input from an HTTP request and passes it into a system-level command execution path without sufficient sanitization or neutralization of shell metacharacters. This is a classic OS command injection pattern classified under CWE-78.

An authenticated user with access to the configuration upload endpoint can embed shell metacharacters or command separators inside request parameters or uploaded file content. When the router's backend invokes a shell to process the upload, injected commands execute in the context of the web service, which on embedded routers typically runs with elevated or root privileges. The attack vector is network-based, requires no user interaction, and can compromise confidentiality, integrity, and availability of the device.

Root Cause

The root cause is improper neutralization of special elements used in an OS command. The configuration upload handler concatenates attacker-controlled input into a command string executed by a system shell. Metacharacters such as ;, |, &, and backticks are not filtered or escaped, allowing arbitrary commands to be appended to the intended operation.

Attack Vector

Exploitation requires valid credentials to the router's web interface. Once authenticated, the attacker issues a crafted HTTP request to the configuration upload endpoint containing a malicious payload in a parameter that reaches the shell. The injected command runs with the privileges of the web management process. Credentials may be obtained through default password reuse, credential stuffing, phishing of network administrators, or prior compromise. See the Talos advisory TALOS-2024-1954 for the technical proof-of-concept details.

No verified public exploit code is available at this time. Refer to the linked advisory for reproduction specifics.

Detection Methods for CVE-2024-21786

Indicators of Compromise

HTTP POST requests to the router configuration upload endpoint containing shell metacharacters such as ;, |, &&, or backticks in parameter values or filenames.
Unexpected outbound connections originating from the router to unknown external hosts, indicating reverse shells or data exfiltration.
New or modified system binaries, cron entries, or startup scripts on the router filesystem.
Unauthorized administrative logins to the web interface, especially from atypical source IPs or outside maintenance windows.

Detection Strategies

Inspect web server access logs on the router for POST requests targeting configuration upload URLs with anomalous payloads.
Correlate authentication events with subsequent upload requests to identify credential-based abuse.
Deploy network intrusion detection signatures matching shell metacharacter patterns in HTTP requests directed at MC LR Router management interfaces.

Monitoring Recommendations

Forward router syslog and web interface access logs to a centralized SIEM for retention and correlation.
Alert on any successful authentication to the router followed by configuration upload activity from non-administrative source ranges.
Monitor for new outbound sessions from the router to non-corporate destinations, which may indicate post-exploitation command-and-control activity.

How to Mitigate CVE-2024-21786

Immediate Actions Required

Restrict access to the router web management interface to trusted management VLANs or jump hosts using network access control lists.
Rotate all administrative credentials for the MC LR Router and enforce strong, unique passwords.
Disable the web interface on WAN-facing interfaces if remote administration is not required.
Audit account activity and configuration upload logs for indicators of prior exploitation.

Patch Information

No vendor advisory URL was published in the CVE record at the time of writing. Administrators should contact MC Technologies directly and monitor the Talos advisory TALOS-2024-1954 for updated fix availability. If a firmware release later than 2.10.5 is offered by the vendor that addresses this issue, apply it after validating in a staging environment.

Workarounds

Segment the router's management plane onto a dedicated administrative network unreachable from user or internet-facing segments.
Place the router behind a firewall that terminates and inspects HTTP traffic to the management interface, blocking requests containing shell metacharacters.
Limit the number of accounts with configuration upload privileges to the minimum required for operations.
Enable multi-factor authentication on any upstream identity provider that gates access to the management network.

bash

# Example: restrict web management access to a specific admin subnet using iptables on an upstream gateway
iptables -A FORWARD -p tcp -s 10.10.50.0/24 -d <router_ip> --dport 443 -j ACCEPT
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -j DROP
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -j DROP