Atomicorp WAF Research Note: CVE-2017-6884

Zyxel_ EMG2926 < V1.00(AAQT.4)b8 - OS Command Injection

CVE Details

• Already protected by existing Atomicorp WAF rules
• Protection status: Understanding Atomicorp WAF Protection Status
• CVE: CVE-2017-6884
• Name: Zyxel_ EMG2926 < V1.00(AAQT.4)b8 - OS Command Injection
• Severity: High
• CVSS: 8.8 (v3.1) (High)
• CVSS version: 3.1
• CVSS source: NVD
• CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
  • Attack vector: Network
  • Attack complexity: Low
  • Privileges required: Low
  • User interaction: None
  • Scope: Unchanged
  • Confidentiality impact: High
  • Integrity impact: High
  • Availability impact: High
• CWE: CWE-78 — Improper Neutralization of Special Elements used in an OS Command (‘OS Command Injection’)
• Related CAPEC attack patterns (via MITRE CWE relationships): CAPEC-108 (opens in a new tab) , CAPEC-15 (opens in a new tab) , CAPEC-43 (opens in a new tab) , CAPEC-6 (opens in a new tab) , CAPEC-88 (opens in a new tab)
• Vendor: zyxel
• Vulnerable product: emg2926 firmware
• CVE published: 2017-04-06
• CVE last modified: 2026-08-04
• Affected versions (NVD configurations):
  • emg2926 firmware: v1.00(aaqt.4)b8
• EPSS: 0.3677; 98.4th percentile (FIRST (opens in a new tab) )
• CISA KEV: Listed (added 2023-09-18)
  • Known ransomware campaign use: Known
• Latest Update: 2026-09-12
• Selected Rule IDs observed: 340014 , 340023 , 340029 , 340193 , 344360 , 344361 , 344363 , 344364 , 344366 , 344370 , 347009 , 390500 , 393655
• Matching rules: 13; rules with blocking actions: 12
• Would-block Rule IDs: 340014 , 340023 , 340029 , 340193 , 344360 , 344361 , 344363 , 344364 , 344366 , 344370 , 347009 , 393655
• Request surfaces inspected: JSON request data, Request URI, Request argument names, Request arguments, Request cookies, SOAP request data, XML request data

Vulnerability Description

A command injection vulnerability was discovered on the Zyxel EMG2926 home router with firmware V1.00(AAQT.4)b8. The vulnerability is located in the diagnostic tools, specifically the nslookup function. A malicious user may exploit numerous vectors to execute arbitrary commands on the router, such as the ping_ip parameter to the expert/maintenance/diagnostic/nslookup URI.

Recommended Actions

1. Maintain the observed Atomicorp protections. Keep your Atomicorp commercial rules current and confirm that the selected observed rules (340014 , 340023 , 340029 , 340193 , 344360 , 344361 , 344363 , 344364 , 344366 , 344370 , 347009 , 393655 ) have not been locally disabled. Atomicorp commercial rules are enabled by default. If you use Atomic WAF, review the applicable policy and rule settings.

2. Apply the vendor’s remediation. WAF protection is defense in depth and does not replace upgrading or following the affected vendor’s guidance.

   • No specific CNA/vendor solution or workaround is included in the current CVE Record (opens in a new tab) . Review the vendor’s security advisories and supported-release guidance before making changes.
   • CISA KEV required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
   • CISA KEV federal remediation due date: 2023-10-09

3. Validate after changes. Confirm rule updates are current, review WAF events for the affected application, and test application behavior after vendor upgrades, mitigations, or local policy changes.

Research Notes

Atomicorp WAF protections are designed around attack techniques and exploit behaviors, allowing existing protections to apply across multiple vulnerabilities without requiring a unique rule for every CVE.

Public Vulnerability References

• NVD (opens in a new tab)
• CVE Record (opens in a new tab)
• Exploit or technical research: https://www.exploit-db.com/exploits/41782/ (opens in a new tab)
• CVE authority reference: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-6884 (opens in a new tab)

Test or Research Source

• Source: Exploit-DB 41782 (opens in a new tab)
• Tags: CVE-2017-6884, cve, derived, exploitdb, http, rce, replay, waf-probe

Research Note Context

This research note documents exploit-technique analysis associated with this vulnerability and references Atomicorp WAF protections observed during engineering review, testing, or validation activities.

Atomicorp security controls are generally designed to identify and mitigate attack techniques and exploit behaviors rather than individual CVE identifiers. As a result, protections developed for one vulnerability may also apply to related attack variants and future vulnerabilities using similar techniques.

Learn More

Atomicorp develops commercially supported security technologies for web applications, servers, endpoints, workloads, and legacy enterprise platforms.

Organizations interested in protecting systems against exploit techniques associated with vulnerabilities such as this one can learn more about:

• Atomic ModSecurity Rules: commercially maintained WAF rules for ModSecurity deployments, including protections for web attacks, bots, scanners, malware, exploitation attempts, and emerging vulnerability classes.
• Atomic WAF: an enterprise web application firewall with Atomicorp rules, centralized management, reporting, authentication controls, and operational tooling.
• Atomic ModSecurity Integrator: a special licensing option for MSPs, MSSPs, OEMs, VARs, reverse proxy providers, and other integrators who want to incorporate Atomicorp ModSecurity rule technology into their own products or services.
• Atomic OSSEC: an enterprise OSSEC-based intrusion detection, compliance, and security monitoring platform.
• Atomic Protector: workload protection for Linux, web, cloud, data center, and hybrid environments.

For additional information, product evaluations, or technical discussions, visit https://www.atomicorp.com/ or https://modsecurity.io/ (opens in a new tab) .