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CVE-2018-25317: Tenda W309r Firmware: Authentication bypass

CVE-2018-25317 is rated critical with a CVSS v3.1 base score of 9.8 and NVD lists 3 affected products, including Tenda W309r Firmware. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available.

Vulnerability description

Tenda W3002R/A302/W309R wireless routers version V5.07.64_en contain a cookie session weakness vulnerability that allows unauthenticated attackers to modify DNS settings by exploiting insufficient session validation. Attackers can send GET requests to the /goform/AdvSetDns endpoint with a crafted admin language cookie to change primary and secondary DNS servers, redirecting user traffic to malicious DNS servers.

Severity breakdown

CVSS v3.1 9.8: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: None. No account or prior access is needed.
  • User interaction: None. No action from any user is needed.
  • Scope: Unchanged. Impact stays within the vulnerable component.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-290: Authentication Bypass by Spoofing

This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.

Affected products

  • Tenda W309r Firmware: 5.07.64_en
  • Tenda A302 Firmware: 5.07.64_en
  • Tenda W3002r Firmware: 5.07.64_en

References