Massive Spam Operation Hijacks Trusted Brands: Over 8,000 Domains Compromised

A large-scale malicious campaign, dubbed “SubdoMailing” by security researchers at Guardio Labs, has come to light. This campaign involves the hijacking of over 8,000 domains and a staggering 13,000 subdomains belonging to well-established and trusted brands and institutions. This activity, believed to have been ongoing since at least September 2022, highlights the growing sophistication of cybercriminals and the ever-present threat of spam and phishing attacks.

Modus Operandi:

The attackers behind SubdoMailing leverage compromised legitimate domains and subdomains to distribute spam emails on a massive scale. These emails often appear to originate from trusted senders, making them difficult for recipients to identify as malicious. The content of these emails varies, ranging from seemingly harmless “counterfeit package delivery alerts” to blatant attempts to steal user credentials through phishing tactics.

Impact and Concerns:

The widespread nature of this campaign raises significant concerns for several reasons:

  • Increased Risk of Phishing Attacks: By leveraging the legitimacy associated with compromised brands, attackers can significantly increase the success rate of phishing attempts, potentially tricking unsuspecting users into revealing sensitive information.
  • Erosion of Trust: The compromise of trusted brands can damage user confidence in online interactions, making it harder for legitimate businesses and institutions to conduct communication through email.
  • Difficulty in Detection: The use of legitimate domains and subdomains makes it challenging for spam filters and email security systems to effectively identify and block malicious emails.


To protect yourself from falling victim to SubdoMailing or similar campaigns, it’s crucial to exercise caution and vigilance when dealing with emails:

  • Be wary of unsolicited emails: Even if an email appears to come from a familiar sender, be cautious of any unexpected content or requests.
  • Verify sender legitimacy: Do not click on links or attachments in emails unless you are absolutely certain of the sender’s identity. Independently verify the sender’s email address by checking their official website or contacting them through a trusted channel.
  • Enable strong spam filtering: Utilize robust spam filtering tools in your email client or rely on security software that can help identify and block malicious emails.
  • Maintain skepticism: If something seems too good to be true, it probably is. Be skeptical of any emails offering unexpected deals, prizes, or other incentives.

By remaining vigilant and following these recommendations, you can significantly reduce the risk of falling victim to SubdoMailing and similar email-based threats. Remember, staying informed about the latest cyber threats and adopting safe online practices are crucial steps in protecting yourself and your information in the digital age.

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