Overview
CVE-2018-25125 describes a buffer overflow vulnerability found in the Netis ADSL Router DL4322D firmware RTK 2.1.1. This flaw resides in the router’s embedded FTP service. By exploiting this vulnerability, an authenticated attacker can trigger a denial-of-service (DoS) condition, effectively rendering the router and its network unavailable.
Technical Details
The vulnerability stems from insufficient input validation within the FTP service. Specifically, when processing FTP commands, such as ABOR, the service fails to properly limit the length of the arguments passed to these commands. By sending an FTP command with an excessively long argument, an attacker can overflow the buffer allocated for that argument, overwriting adjacent memory regions. This memory corruption leads to the FTP service, and often the entire router system, crashing or becoming unresponsive. Authentication to the FTP service is required to trigger the vulnerability.
Firmware Version: RTK 2.1.1
CVSS Analysis
Unfortunately, the CVSS score for CVE-2018-25125 is not explicitly provided in the given information. However, based on the description, the vulnerability results in a denial-of-service, and authentication is required. A reasonable estimation would put it in the Medium severity range, given the need for authentication, but lack of impact to confidentiality or integrity.
Possible Impact
The exploitation of CVE-2018-25125 can have several detrimental impacts:
- Denial of Service (DoS): The primary impact is the disruption of network services for all users connected to the affected router.
- Loss of Connectivity: Users will be unable to access the internet or other network resources.
- Business Disruption: For businesses relying on the affected router, the DoS can lead to significant operational downtime and financial losses.
Mitigation or Patch Steps
Unfortunately, official support for the Netis DL4322D router appears to be limited. However, here are possible mitigation steps:
- Upgrade Firmware (if available): Check the Netis website for any available firmware updates for the DL4322D model. Note that while a link to the router details page was active previously, it is no longer available on the website.
- Disable FTP Service: If the FTP service is not essential, disabling it within the router’s configuration interface will eliminate the vulnerability.
- Network Segmentation: Isolate the router from critical network segments to limit the impact of a potential DoS attack.
- Monitor Network Traffic: Implement network monitoring solutions to detect and respond to suspicious activity targeting the router’s FTP service.
- Use a Strong Password: Ensure a strong and unique password is used for the router’s FTP service.
