$12.5B
FTC-reported fraud losses in 2024
FTC says consumers reported losing $12.5 billion to fraud in 2024.
reply-chain hijacking scam
Attackers compromise an email account and insert malicious messages into existing email threads, exploiting the trust established in ongoing conversations.
“phishing email”
↑ 215%Key indicators
Usually targetsOffice workers
Often hitsFreelancers and contractors
Common regionUnited States
Last updated2026-04-04
Estimated impact
$900
median reported loss
Typical range$90 – $9.0K
Recovery rate~18%
Annual reports290,000
Scam breakdown
1
Attackers compromise one participant's email account and read existing conversations to find valuable threads.
2
They reply within the thread with a malicious attachment or link, appearing as a natural continuation of the conversation.
3
Because the message appears in a trusted thread, recipients are far more likely to open attachments or click links.
What to do first
Be cautious of unexpected attachments or links even in existing email threads.
Related terms
thread hijacking attackconversation injectionemail thread poisoningEmail phishing scamsEmailSurgingOffice workersExecutivesIT administratorsFreelancers and contractorsSmall business ownersPayroll, HR, and finance teamsUnited StatesUnited KingdomGermanythread hijacking attackconversation injection
Real-world example
How this scam plays out in practice
Based on reported patterns. Names and details are illustrative.
The setup
James, 35, a office workers, encountered what appeared to be a legitimate email phishing scams situation while using Email. Attackers compromise one participant's email account and read existing conversations to find valuable threads.
Step 2
What happened next was calculated: They reply within the thread with a malicious attachment or link, appearing as a natural continuation of the conversation.
Step 3
The pressure escalated quickly: Because the message appears in a trusted thread, recipients are far more likely to open attachments or click links.
The outcome
James realized something was wrong when a reply in an existing thread contains an unexpected attachment or link. By that point, significant damage had already been done — money sent, personal information shared, or trust exploited.
The lesson
Be cautious of unexpected attachments or links even in existing email threads. James's experience shows why a reply in an existing thread contains an unexpected attachment or link and the tone or writing style suddenly changes mid-conversation are the clearest early warning signs.
How to identify it
- A reply in an existing thread contains an unexpected attachment or link
- The tone or writing style suddenly changes mid-conversation
- The reply asks you to take action unrelated to the original topic of discussion
- Pause before paying, clicking, or sharing information. Scammers rely on speed.
- Verify the sender, company, or agency using a phone number or website you already know is legitimate.
- Treat secrecy, urgency, and off-platform payment requests as strong scam signals.
What to do now
- ✓Be cautious of unexpected attachments or links even in existing email threads.
- ✓Contact the sender through a separate channel if a reply seems out of context.
- ✓Implement email authentication protocols (DMARC, DKIM, SPF) to reduce spoofing in your organization.
What to save before reporting
- ✓Save the message, profile, phone number, email, or URL that was used.
- ✓Keep payment confirmations, receipts, and account alerts before you dispute or delete anything.
- ✓Write down the timeline while the details are still fresh.
- ✓Keep the full sender address, domain, attachments, and—if possible—the raw email headers.
How big is this problem
You are not alone — this scam affects millions of people.
These numbers come from government agencies and official reports. If you have been affected, know that this is a widespread problem — not something that only happens to careless people.
FTC 2024 fraud losses
Imposters
Most common FTC fraud category in 2024
FTC says imposter scams remained the most commonly reported fraud category in 2024.
History and evolution
- This scam family tends to persist because the social-engineering pressure works even when the exact scripts, platforms, and payment methods change.
- The specific packaging evolves over time, but the core pattern usually stays the same: create urgency, control the channel, and push action before verification.
- Proofpoint and other security firms have documented a significant rise in thread hijacking attacks, noting that response rates to these emails are substantially higher than standard phishing.
Recovery and follow-up
- ✓Save the messages, receipts, account alerts, and transaction details before you block or delete anything.
- ✓Report the scam through the official platform or government channel that best matches where it happened.
- ✓Be cautious of unexpected attachments or links even in existing email threads.
- ✓Contact the sender through a separate channel if a reply seems out of context.
- ✓Implement email authentication protocols (DMARC, DKIM, SPF) to reduce spoofing in your organization.
Why this pattern keeps working
Even when the story changes, most scams still use the same pressure pattern: urgency, authority, and a request to move money or data fast.
Proofpoint and other security firms have documented a significant rise in thread hijacking attacks, noting that response rates to these emails are substantially higher than standard phishing.
OpenScam research
Where to report it
If you have been targeted by this scam, reporting it helps authorities track the pattern and protect others. United States has dedicated agencies that handle fraud reports.
ReportFraud.gov
Federal Trade Commission
Central U.S. consumer fraud reporting portal.
File an IC3 complaint
FBI Internet Crime Complaint Center
FBI portal for internet-enabled crime reports.
Start identity theft recovery
IdentityTheft.gov
Official U.S. identity theft recovery plan builder.
Explore further
Understand the bigger picture
Who is most at risk
Who this scam targets
Primary targets
Office workers, Executives, IT administrators
Geographic concentration
United States, United Kingdom, Germany, Canada
Primary channel
Email — Email phishing scams
Why this group is vulnerable
Office workers are particularly vulnerable because this scam exploits trust in familiar brands, authority figures, and time-sensitive decisions. The rapid increase in reports suggests that awareness among this demographic remains low.
Sources and methodology
How we verify this information
OpenScam tracks scam patterns using a combination of government consumer protection databases (FTC, IC3, Action Fraud), platform-specific fraud reports, and verified consumer complaint data. Each entry is cross-referenced against at least two independent sources before publication.
Severity ratings are based on financial impact potential, reversibility of damage, and volume of reports across multiple reporting channels. Trend velocity reflects the rate of change in report volume over the most recent 90-day window.
This page was last verified on 2026-04-04. Red flags, recovery steps, and reporting resources are reviewed quarterly against current agency guidance.
Evidence and indicators
- Proofpoint and other security firms have documented a significant rise in thread hijacking attacks, noting that response rates to these emails are substantially higher than standard phishing.
Source notes
- OpenScam research
Frequently asked questions
Common questions about reply-chain hijacking scam
How does the reply-chain hijacking scam work?+
Attackers compromise one participant's email account and read existing conversations to find valuable threads. They reply within the thread with a malicious attachment or link, appearing as a natural continuation of the conversation. Because the message appears in a trusted thread, recipients are far more likely to open attachments or click links.
What are the warning signs of reply-chain hijacking scam?+
A reply in an existing thread contains an unexpected attachment or link The tone or writing style suddenly changes mid-conversation The reply asks you to take action unrelated to the original topic of discussion
What should I do if I encounter reply-chain hijacking scam?+
Be cautious of unexpected attachments or links even in existing email threads. Contact the sender through a separate channel if a reply seems out of context. Implement email authentication protocols (DMARC, DKIM, SPF) to reduce spoofing in your organization.
Who is most at risk for reply-chain hijacking scam?+
This scam primarily targets Office workers, Executives, IT administrators. It is most commonly reported in United States, United Kingdom, Germany, Canada and typically appears on Email.
Is reply-chain hijacking scam getting worse?+
reply-chain hijacking scam is currently surging — reports are increasing rapidly. It has been reported across US, UK, DE, CA. Last updated 2026-04-04.
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Help someone avoid this scam.
Scammers succeed because people do not talk about it. If you or someone you know has been affected, there is no shame in it — it happens to millions of people every year. Share this page with friends and family so they know what to look for.
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