What is clone phishing?

Clone phishing is a type of phishing attack where a cybercriminal copies (or “clones”) a legitimate email that the victim has previously received, then resends it with a malicious link or attachment substituted for the original content.

How does clone phishing work?

Unlike generic phishing that relies on generic mass emails, clone phishing leverages the familiarity of an existing, previously delivered message, making it much harder for users to detect that something is wrong. 

According to the study Clone Phishing: Attacks and Defenses, the key steps in a clone phishing attack include:

• Duplicate a legitimate message: The attacker starts by copying the content of a real email that the victim has received from a trusted sender. This could be a bank statement, a shared document notification, or a corporate communication. 
• Modify links or attachments: The cloned email is altered to replace original links or attachments with malicious ones. These can point to credential-harvesting sites or malware downloads while maintaining the look and feel of the original message. 
• Spoof sender information: Cybercriminals often spoof the email address or display name of the sender so that the message appears to come from someone within the organization or a known external party. 
• Create fake login pages: If the malicious link leads to a website, attackers can build fake login pages that closely mimic legitimate ones. When the victim enters their credentials, those details are captured by the attacker. 
• Targeting and social engineering: Clone phishing attacks may be highly targeted (similar to spear phishing), with attackers using social engineering to tailor messages so they appear more convincing to specific individuals or groups. 

Defending against clone phishing

Defending against clone phishing requires a combination of user awareness, technical controls, and secure processes to reduce the risk of compromise. The study also lists effective countermeasures to defend against clone phishing attacks: 

• User education and awareness: Training users to recognize suspicious emails, including those that appear familiar, is one of the most impactful defenses. Awareness programs should teach how to inspect email headers, verify links, and question unexpected requests for information. 
• Two-factor authentication (2FA): Implementing multi-factor authentication (MFA) adds a layer of security so that even if credentials are stolen via a cloned phishing attempt, attackers cannot easily access accounts without a second form of verification. 
• Anti-phishing software: The article suggests deploying email security tools that use machine learning and reputation analysis to detect and block fraudulent emails and malicious links before they reach users’ inboxes. 
• Website verification: Use services and tools that verify the legitimacy of websites by checking SSL certificates and consulting known malware or phishing blacklists. This helps users and security systems identify suspicious sites masquerading as legitimate. 
• Email authentication protocols: Implement protocols like DMARC, SPF, and DKIM to help prevent email spoofing. These make it harder for attackers to send messages that appear to come from legitimate domains. 
• Regular software updates: Keeping operating systems, browsers, and security software up to date helps eliminate vulnerabilities that attackers might exploit in conjunction with phishing.

Read also: Steps to protect against phishing attacks

How Paubox enhances protection against clone phishing

Paubox can help protect against clone phishing by using AI-powered inbound email security that analyzes sender behavior, message context, and intent to identify phishing attempts that closely mimic legitimate emails. Because clone phishing relies on familiarity, Paubox’s ability to detect subtle anomalies in tone, links, and sender patterns is key to stopping these attacks before they reach inboxes.

Paubox also combats one of the core tactics of clone phishing, sender impersonation, through advanced anti-spoofing protections like ExecProtect+, which block emails that falsely appear to come from trusted executives, employees, or known contacts. Combined with multi-layered filtering, link and attachment scanning, and quarantine controls, Paubox reduces the risk that cloned emails can lead to credential theft, malware infection, or HIPAA-related data breaches.

See also: HIPAA Compliant Email: The Definitive Guide (2025 Update)

FAQS

What are the typical goals of clone phishing?

The primary goal is to trick the recipient into clicking malicious links or downloading harmful attachments that can steal sensitive data, install malware, or compromise accounts.

How can I recognize a clone phishing email?

Signs include unexpected requests for sensitive information or actions, slight changes in sender email addresses, unusual or mismatched URLs, and attachments that the original email did not contain.

What should I do if I suspect a clone phishing email?

Do not click any links or download attachments. Verify the email’s authenticity by contacting the sender through a trusted method, and report the email to your IT department or email provider.

Can email security solutions detect clone phishing?

Some advanced email filters and security tools can detect clone phishing by analyzing email headers, attachment signatures, and link behavior, but user vigilance remains critical.