Your Message Is Too Large To Be Delivered Email Scam

The 'Your Message Is Too Large To Be Delivered' scam is a phishing campaign disguised as an automated email delivery failure notice. The message attempts to convince recipients that an outgoing email could not be delivered because it exceeded the server's attachment size limit.

Typically, the email includes a subject line such as 'Please confirm to continue' and claims that the recipient attempted to send a message weighing 40 MB, which allegedly exceeds a 36 MB limit imposed by the server. To reinforce the illusion of legitimacy, the message contains a button labeled 'View failed delivery.'

The primary purpose of this email is not to notify users about delivery issues. Instead, the scammers aim to lure recipients into clicking the embedded link and entering their login credentials on a fraudulent website.

The Fake Roundcube Webmail Page

Recipients who click the provided button are redirected to a counterfeit login page that imitates the appearance of Roundcube Webmail. The phishing page requests the victim's full email address and password, creating the false impression that authentication is required to review the failed message.

Investigations into the scam reveal that the fake login page is sometimes hosted through Google's cloud storage infrastructure. Cybercriminals commonly abuse legitimate hosting platforms because the URLs may appear trustworthy at first glance, making victims less suspicious.

It is important to understand that Roundcube has absolutely no involvement in this phishing operation. Its branding and interface are being misused without authorization solely to make the fraudulent page appear authentic.

What Happens After Credentials Are Stolen

Any information entered into the fake login form is transmitted directly to the attackers. Once cybercriminals gain access to an email account, the consequences can be severe.

Compromised email accounts may be used to:

• Read confidential conversations and sensitive personal information
• Impersonate the victim to deceive contacts or business associates
• Launch additional phishing attacks from a trusted account
• Attempt password resets for banking, shopping, or social media services connected to the stolen email address
• Distribute spam, scams, or malicious files to other users

Because email accounts are often linked to numerous online services, a single stolen password can quickly lead to broader account compromise and identity-related fraud.

Malware Risks Associated With Spam Campaigns

Phishing campaigns such as this one are not always limited to credential theft. Many spam operations are also used to distribute malware through malicious attachments or dangerous links.

Cybercriminals may attach harmful files in several formats, including executable programs, archive files, PDF documents, Microsoft Office files, and scripts. In some cases, simply opening the file may initiate the infection process. In others, users are tricked into enabling macros or additional features that activate the malware.

These infections can lead to serious security problems, including ransomware attacks, spyware installation, data theft, and unauthorized remote access to infected systems.

Warning Signs That Reveal the Scam

Although the emails are designed to appear convincing, several red flags can help recipients identify the fraud:

• Unexpected delivery failure notifications for messages the recipient never sent
• Pressure to click buttons or verify information immediately
• Requests for email passwords through external login pages
• Suspicious wording, formatting inconsistencies, or unusual sender addresses
• Login pages hosted on unrelated or suspicious domains

Users should remember that legitimate email providers do not request passwords through unsolicited delivery failure notices.

• How to Stay Protected

Recipients who receive these emails should avoid clicking any links or downloading any attachments. The safest response is to delete the message immediately.

Anyone who has already entered credentials on the fraudulent page should change their email password without delay. It is also strongly recommended to enable two-factor authentication, review account activity for unauthorized access, and update passwords for other accounts linked to the compromised email address.

Maintaining strong cybersecurity habits, remaining skeptical of unexpected messages, and carefully verifying login pages are essential steps in defending against phishing attacks like the 'Your Message Is Too Large To Be Delivered' scam.

Final Thoughts

The 'Your Message Is Too Large To Be Delivered' emails are fraudulent phishing messages created to steal email login credentials. By impersonating a delivery failure notification and misusing Roundcube branding, cybercriminals attempt to manipulate recipients into surrendering sensitive information.

These emails should never be trusted. Ignoring and deleting them immediately is the best course of action, while users who interacted with the scam should take prompt security measures to protect their accounts and personal data.