DrayTek VigorConnect - LFI (CVE-2021-20124)

CVE-2021-20124 is a vulnerability present in DrayTek VigorConnect that allows unauthenticated attackers to perform local file inclusion through the WebServlet endpoint, which could enable the unauthorized download of arbitrary files with elevated privileges.

CrowdSec has been tracking this vulnerability and its exploits since 10th of March 2025.

CrowdSec network observations suggest that most exploitation of CVE-2021-20124 involves focused reconnaissance to identify viable targets. Attackers typically tailor their campaigns based on system exposure and configuration. It is unlikely that a given attack is accidental. Data from the CrowdSec community also indicates a gradual decrease in attacks targeting CVE-2021-20124. While still present in the wild, exploitation levels have dropped noticeably week-over-week. This may signal that the vulnerability is becoming less relevant or that defenses are improving fast enough for attackers to lose interest.

Exploitation attempts typically involve requests to URLs containing both acsserver/webservlet and act=getmapimg_acs2.