# CVE-2021-20124: DrayTek VigorConnect - LFI

> Live exploitation tracking for CVE-2021-20124 by the CrowdSec Live Exploit Tracker, built from real-world attack data crowdsourced from CrowdSec's global network.

Page: https://tracker.crowdsec.net/cves/CVE-2021-20124

## Key facts

- **Exploitation phase:** Limited Exploitation. The vulnerability is known but shows very limited attacker interest or exploitation activity.
- **CVSS score:** 7.5
- **Public exploit available:** Yes
- **Affected products:** DrayTek VigorConnect
- **Weaknesses:** CWE-22 (Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'))

## Description

A local file inclusion vulnerability exists in DrayTek VigorConnect 1.6.0-B3 in the file download functionality of the WebServlet endpoint. An unauthenticated attacker could leverage this vulnerability to download arbitrary files from the underlying operating system with root privileges.

## CrowdSec analysis

[CVE-2021-20124](https://euvd.enisa.europa.eu/vulnerability/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 24th of September 2024.

According to CrowdSec data, while opportunistic exploitation dominates, a portion of threat actors trying to exploit CVE-2021-20124 apply basic targeting methods such as port or service detection. This indicates emerging patterns of selective targeting.
CrowdSec data also reveals a clear uptick in attacks involving CVE-2021-20124 over the past week. Activity is above the usual baseline, suggesting growing attention from attackers. This may reflect rising awareness, recent exploit releases, or expanded targeting efforts.

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

## Timeline

- 2021-10-13: CVE Published. CVE-2021-20124 is published to NVD.
- 2024-09-03: CISA KEV. CVE-2021-20124 is added to the Known Exploited Vulnerabilities catalog by CISA.
- 2024-09-24: Rule Released. CrowdSec releases a rule to detect CVE-2021-20124 exploitation attempts against the CrowdSec Network.
- 2024-09-24: CISA Remediation Deadline. Expiration of the CISA remediation deadline as described in [BOD 22-01](https://www.cisa.gov/news-events/directives/bod-22-01-reducing-significant-risk-known-exploited-vulnerabilities).
- 2024-11-23: CrowdSec First Seen. CrowdSec observes in-the-wild exploitation of CVE-2021-20124 for the first time.

## References

- https://www.tenable.com/security/research/tra-2021-42
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-20124.yaml

## Live exploitation data

The [Live Exploit Tracker page](https://tracker.crowdsec.net/cves/CVE-2021-20124) follows observed exploitation activity for CVE-2021-20124. [Request an API key](https://tracker.crowdsec.net/request-api-key) for full access to its exploitation timeline, attacking IP addresses and blocklists.