**[Cybersecurity Report] A Record of a Phishing Attack Targeting an ACGN Forum Operations Team**

Terrible! ヽ(*。>Д<)o゜

Prior Notice: The team has only two official email addresses: [email protected] and [email protected]

Do not blindly trust all emails in the “Spam” folder—verify with the official team if necessary!


Summary

On 2026-02-18 at 01:18 (UTC), the forum admin received a suspicious phishing email from <[email protected]> addressed to [email protected]. After internal verification, the team confirmed that the email address [email protected] does not exist, and the email exhibited classic signs of forgery and phishing. The intent appears to be credential theft by impersonating an email storage management portal via deceptive links. Key findings include obfuscated content, suspicious domain redirects, and association with high-abuse top-level domains (TLDs). The target link’s .sbs TLD has a reported abuse rate of 225.9 in recent investigations.

Notably, the team received an identical phishing email at 13:48 (UTC) the same day. Neither email contained trackers in the body.

Both phishing emails failed DKIM signature verification and were filtered into the “Spam” folder.


Email Header Analysis

The email was relayed through multiple servers, originating from a Google Cloud IP (35.204..) before reaching the team’s mail server. Analysis by the security team revealed that the “From” field in the raw email was empty (<>), indicating this was not a standard email. The team’s spam filter successfully identified and blocked it. The header was marked with high-priority flags (Importance: high, X-Priority: 1).

The content used base64 encoding for both plaintext and HTML sections—a common tactic to evade spam detection. The MIME-Version: 1.0 and multipart/alternative structure mimicked professional emails.


Sender Analysis

Sent via a Google Cloud virtual instance, a common practice in phishing campaigns.


Content Analysis

Email Screenshot

Subject: [[email protected]]: Please confirm to continue.
Impersonates internal support to establish trust.

Body: Claims the mailbox is nearly full (49.5 GB / 50 GB) and will be unable to send/receive emails within 24 hours, urging immediate action. This fear-based tactic is a hallmark of phishing, pressuring recipients to click without verification.
The body also includes HTML elements—a progress bar (red background to create urgency) and a “Clear Cache” button—along with a confidentiality disclaimer to mimic corporate emails.

Notably, the phrase “EMail storage portal” is improperly capitalized.


Link and Redirect Analysis

The embedded link follows this structure:
https://juguetes[redacted to prevent victimization].com.ar/Banner.php?id=21&url=https://do[redacted to prevent victimization].sbs/tang/index.html?email=[Email]

  • juguetes[redacted].com.ar is a legitimate Argentine toy company (founded in the 1990s). The /Banner.php path suggests a possible compromise, such as an injected redirect script.
  • The target is do[redacted].sbs. The .sbs TLD is flagged for high phishing abuse, with 10% of domains recently classified as malicious. Spamhaus reports a 172% growth rate in .sbs registrations, with escalating abuse due to low registration costs. Users on platforms like Reddit have reported spam from .sbs domains, often displaying “Insufficient relevant content” or Cloudflare verification—common in hidden phishing pages that dynamically load to evade detection.

The likely goal is credential theft (e.g., email/password). The ?email=[Email] parameter suggests a pre-filled form.


Conclusion

This is terrifying! ヽ(*。>Д<)o゜

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The sender may specifically target org domains,

using crawlers to scrape active websites with .org suffixes, then employing scripts to send phishing emails in bulk to .org domain addresses.

This is a suspicious link~ Think about it :pleading_face:

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How to put it—was the DNS tampered with, or did someone use a method to delete the sender’s email address and forge your email name in the “From” field?

Can you send me the EML file privately?

The Security Department has completed all analyses and further improved the team’s email security configuration. Do not blindly trust all emails in the “Spam” folder—if necessary, verify with the official team!


This is a design flaw in SMTP—senders can freely spoof addresses, but receiving servers can verify emails to decide whether to accept or reject them.


Scary stuff! ヽ(*。>Д<)o゜

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SMTP again.