External risk intelligence

Zyxel DSL CPE Command Injection Vulnerability.

CVE advisoryKnown Exploit

CVE-2024-40890

The affected devices are DSL CPE (Customer Premises Equipment) modems and gateways. These devices serve as the edge network interface between an ISP and the customer, and their administrative management interfaces are commonly exposed or reachable, making them a typical target for network-adjacent access in real-world deployment patterns.

OS Command Injection

Zyxel Vmg1312 B10a Firmware

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

A command injection vulnerability exists within the CGI program of certain Zyxel DSL Customer Premises Equipment (CPE) devices. This flaw allows an authenticated attacker to execute operating system commands on the affected device. The ability to inject commands can lead to unauthorized actions and potential compromise of the device.

  • Vulnerable Zyxel DSL CPE CGI program
  • Allows OS command execution
  • Business risk of device compromise

Attack Path

How an attacker could exploit the issue

A post-authentication command injection vulnerability exists within the CGI program of certain Zyxel DSL CPE devices. An attacker with authenticated access can exploit this by sending a specially crafted HTTP POST request. Successful exploitation allows the attacker to execute operating system commands on the affected device, potentially leading to unauthorized control.

  • Requires authenticated access.
  • Attacker sends crafted HTTP POST.
  • Results in OS command execution.

Live Threat

Current exploitation, exposure, and threat context

A command injection vulnerability exists in specific Zyxel DSL Customer Premises Equipment (CPE) devices. An authenticated attacker could exploit this by sending a specially crafted HTTP POST request. This exploit could enable the attacker to execute operating system commands on the affected device, potentially leading to significant business risk.

  • Attacker skill level: Moderate
  • Required access or conditions: Authenticated access
  • Business risk or urgency: High

Operational Fix

Recommended remediation, mitigation, and detection steps

The organization should address a command injection vulnerability affecting specific Zyxel DSL CPE devices. This vulnerability allows an authenticated attacker to execute operating system commands by sending a specially crafted HTTP request. Such an attack could compromise the affected device and potentially lead to further network intrusion.

  • Identify exposed Zyxel DSL CPE assets.
  • Isolate affected devices if immediate patching is not feasible.
  • Apply vendor updates and validate the fix.
  • Monitor for related suspicious activity.

Supplementary metadata

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Frequently asked questions

What is the Zyxel VMG4325-B10A firmware and its function?

The Zyxel VMG4325-B10A is a legacy DSL Customer Premises Equipment (CPE) device, serving as a modem or gateway to connect a user's network to their Internet Service Provider. This specific firmware version is integral for enabling network connectivity and facilitating device management functions.

How does CVE-2024-40890 enable command injection?

CVE-2024-40890 is a command injection weakness. An authenticated attacker can leverage this by sending a specially crafted HTTP POST request to the device's CGI program, tricking it into executing unintended operating system commands and gaining unauthorized control.

What are the implications of the CVE-2024-40890 vulnerability?

Exploiting CVE-2024-40890 allows an authenticated attacker to execute arbitrary operating system commands on the affected Zyxel DSL CPE device. This poses a significant business risk, potentially leading to device compromise and further network intrusion.

How relevant is CVE-2024-40890, considering Halo Surface Signal?

Halo Surface Signal rates this vulnerability as 'Likely' due to the nature of the affected devices. Zyxel DSL CPEs are edge network devices often accessible and targeted, making them typical targets for network-adjacent attacks that align with real-world exploitation patterns.

What steps should be taken to mitigate the Zyxel DSL CPE command injection vulnerability?

Organizations should identify all exposed Zyxel DSL CPE assets. If immediate patching isn't possible, isolate affected devices. Apply vendor-provided updates and verify the fix, while consistently monitoring for any suspicious network activity.

References