CVE-2023-4415

What it actually does

CVE-2023-4415 is an improper authentication vulnerability in the Ruijie RG-EW1200G router firmware, reported in firmware build 07161417 r483, affecting the /api/sys/login endpoint. A remote attacker can manipulate the login workflow to bypass or defeat intended authentication controls and gain access to privileged router functionality. Because the device is a network edge appliance, successful exploitation can expose administrative configuration, allow unauthorized configuration changes, enable traffic interception or redirection, and potentially disrupt routing or wireless services. The CVSS score is 8.8 and public weaponized exploit activity is reported, meaning exploitation is practical and likely for internet-exposed devices.

Why it matters to the business

Compromise of an affected router can give an attacker control over a network gateway, which may lead to outages, unauthorized network changes, interception or redirection of user traffic, exposure of internal services, and use of the device as a foothold for broader intrusion. The risk is elevated because the issue is remotely exploitable, public exploit code is available, the EPSS score is high, and no fixed version is listed in the provided data, making mitigation and exposure reduction especially important for organizations still using affected Ruijie RG-EW1200G firmware.

How an attack unfolds

An attacker first identifies an exposed Ruijie RG-EW1200G management interface, commonly by internet scanning or targeting known router administration ports. The attacker then sends crafted requests to the /api/sys/login API endpoint that exploit improper authentication handling. If successful, the attacker bypasses normal login requirements or obtains an authenticated administrative session. With administrative access, the attacker can change network, DNS, wireless, firewall, or remote-management settings; create or modify accounts where supported; inspect configuration data; redirect traffic; or make the device unstable or unavailable. Because exploit details have been publicly disclosed and the exploit maturity is weaponized, opportunistic scanning and automated exploitation should be assumed for internet-reachable devices.

How to fix it

Upgrade the Ruijie RG-EW1200G firmware to a vendor-provided fixed release if one is available from official Ruijie support channels. No fixed version was provided in the input data, and the original disclosure notes lack of vendor response, so organizations should treat affected firmware build 07161417 r483 as unsafe until confirmed otherwise by the vendor. If an upgrade is unavailable, reduce exposure immediately: disable internet-facing management access, restrict management to trusted internal administration networks or VPN-only access, block external access to the web administration service at firewalls, use strong unique administrator credentials, disable unnecessary remote administration features, and monitor for configuration changes. Where risk cannot be adequately mitigated, replace the device with a supported model that receives security updates.

How to confirm the fix worked

Confirm the device model and firmware version from the router administration interface, configuration export, asset inventory, or network management platform. Validate that Ruijie RG-EW1200G devices are not running firmware build 07161417 r483 or other unverified vulnerable builds. From an external network perspective, verify that the router management interface and /api/sys/login endpoint are not reachable from the internet or untrusted networks. Review firewall rules, NAT rules, and remote administration settings to confirm management access is restricted to approved administrative sources. After remediation or mitigation, perform an authenticated configuration review and a controlled unauthenticated access test to ensure login bypass behavior is no longer possible and administrative functions require valid authentication.

Typical attack path

1. Scan the internet or target networks for exposed Ruijie RG-EW1200G router management interfaces.
2. Fingerprint the device model, firmware, login page, or API behavior to identify potentially vulnerable firmware.
3. Send crafted HTTP requests to /api/sys/login to trigger the improper authentication weakness.
4. Obtain unauthorized access to the router management API or administrative interface.
5. Modify configuration, add persistence through management settings if possible, change DNS or routing behavior, disable security controls, or disrupt network service.
6. Use the compromised router as a pivot point, proxy, traffic interception point, or platform for additional scanning and attacks.

How to detect it

Investigate whether the router management interface was exposed to untrusted networks and review all available device logs, web access logs from upstream reverse proxies or firewalls, firewall connection logs, VPN logs, and network IDS/IPS telemetry for requests to /api/sys/login. Look for unauthenticated or unexpected HTTP requests to the login API, repeated requests from the same external source, access from unfamiliar countries or hosting providers, and login API access followed by administrative configuration changes. Review router configuration history and backups for unauthorized changes to DNS servers, DHCP options, static routes, firewall rules, port forwarding, remote administration settings, wireless SSIDs, administrator accounts, and firmware settings. Because many small router appliances have limited logging, absence of local evidence should not be treated as proof of non-exploitation; correlate with perimeter firewall, NetFlow, proxy, and IDS records. If compromise is suspected, preserve current configuration and logs, isolate management access, rotate credentials, restore known-good configuration, and consider factory reset or device replacement.

• /api/sys/login
• POST /api/sys/login
• GET /api/sys/login
• RG-EW1200G
• 07161417 r483
• ruijienetworks rg-ew1200g
• VDB-237518

What your security team should do

• Immediately inventory Ruijie RG-EW1200G devices and identify firmware versions, especially build 07161417 r483.
• Treat internet-exposed affected devices as high priority because exploitation is remote, public, weaponized, and has a high EPSS score.
• Disable or firewall off public access to the router management interface and require VPN or trusted management networks only.
• Check Ruijie support channels for updated firmware; if no fixed firmware is available, plan replacement of affected devices.
• Review router configuration for unauthorized DNS, DHCP, routing, firewall, port-forwarding, remote-management, and administrator account changes.
• Rotate router administrator credentials after mitigation and remove any unknown or unnecessary accounts or access methods.
• Collect and preserve available web management logs, system logs, configuration backups, and network telemetry before rebooting or factory resetting suspected compromised devices.
• Add SIEM detections for suspicious access to /api/sys/login, especially from external IP addresses, unusual geographies, high-frequency login attempts, or access followed by configuration changes.