Zero-day vulnerability in DrayTek firmware

Cross-site request forgery

Vulnerability exploitation was spotted by users of DrayTek routers. Attackers used CSRF vulnerability to change DNS settings of multiple routers to address: 38.134.121.95.

Vulnerability details

Advisory: SB2018051901 - CSRF in multiple DrayTek routers

Vulnerable component: DrayTek firmware

CVE-ID:

CVSSv3 score: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N/E:H/RL:O/RC:C

CWE-ID: CWE-352 - Cross-Site Request Forgery (CSRF)

Description:

The vulnerability allows a remote attacker to perform CSRF attacks.

The vulnerability exists due to insufficient validation of the HTTP request origin in DrayTek Vigor web management interface. A remote attacker can change setting of Vigor router.

Note: this vulnerability has been exploited in the wild in May 2018. The attackers changed DNS servers of victims to address: 38.134.121.95

External links:

https://helpforum.sky.com/t5/Sky-Q/Sky-Q-and-Draytek-router/td-p/2835571
https://www.draytek.co.uk/support/security-advisories/kb-advisory-csrf-and-dns-dhcp-web-attacks
https://www.draytek.com/en/about/news/2018/notification-of-urgent-security-updates-to-draytek-router...
https://www.bleepingcomputer.com/news/security/draytek-router-zero-day-under-attack/

About zero-day vulnerabilities

Zero-day vulnerability is an undisclosed vulnerability in software that hackers can exploit to compromise computer programs, gain unauthorized access to sensitive data, penetrate networks, etc. We consider vulnerability a zero-day when there is no solution provided from software vendor and the vulnerability is being actively exploited by malicious actors.

Zero-day candidate is a potential zero-day vulnerability in software which might have been used in targeted attacks, however there is no evidence to support this suggestion.