1. Summary

A subdomain of Target, heyo.redacted.target.comwas pointing to an unclaimed Acquia service endpoint, but remains unclaimed. Although an actual takeover could not be demonstrated because Acquia requires an active paid subscription for domain assignment, the misconfiguration still presents a serious security risk. An attacker with an Acquia subscription could claim this subdomain and host malicious content under the trusted *.target.com domain.

2. Technical Details

A. DNS Resolution

$ dig heyo.redacted.target.com CNAME
;; ANSWER SECTION:
heyo.redacted.target.com. 3395 IN CNAME heyo.redacted.target.com..cdn.cloudflare.net

The subdomain heyo.redacted.target.com points to heyo.redacted.target.com.cdn.cloudflare.net. Typically, it indicates a connection with a service hosted behind Cloudflare.

B. Web Response

$ curl -I https://heyo.redacted.target.com
HTTP/2 404
date: Sat, 26 Apr 2025 18:25:00 GMT
content-type: text/html
server: cloudflare
cf-ray: 93681ec7bd1e7b59-IAD
cf-cache-status: DYNAMIC

The web server returns a "404 Not Found", confirmation that no active web application is linked to the subdomain.

C. Screenshot

Acquia Domain not Found
Acquia Network Domain Not Found

D. Attempt to Claim

An attempt was made to create an Acquia site and add the domain. However:

  • Acquia requires a paid subscription to add custom domains.
  • No free trial or complimentary access was available.
  • As such, a full exploitation (i.e., practical domain claim) was not completed.

Nevertheless, in a real-world threat scenario, an attacker could easily subscribe to Acquia, claim the subdomain, and perform malicious activities under *.target.com.

3. Impact

If exploited, the attacker could:

  • Host phishing pages under a trusted Target domain.
  • Deliver malware payloads to employees or customers.
  • Exploit SSL trust (because the subdomain has a valid DNS/SSL path through Cloudflare).
  • Damage brand reputation if malicious activities are linked to Target's domain.

4. Recommendation

  • Immediately remove or correct the DNS CNAME record for heyo.redacted.target.com If it is no longer needed.
  • Alternatively, claim and properly configure the subdomain within the Acquia platform to prevent external abuse.
  • Audit other DNS records for similar misconfigurations to prevent future occurrences.

Thanks for reading.

./Keep-Hacking