[{"data":1,"prerenderedAt":59},["ShallowReactive",2],{"glossary:thread-hijacking":3},{"term":4,"published":50,"modified":50,"mentions":51,"related":57},{"slug":5,"title":6,"lede":7,"blocks":8,"faqs":37},"thread-hijacking","Thread Hijacking","Thread hijacking injects malicious replies into real, ongoing email conversations, borrowing their trust and context to defeat normal suspicion.",[9,12,15,21,23,25,27,29,31,33,35],{"t":10,"text":11},"p","Thread hijacking (conversation hijacking) is an attack where a criminal inserts themselves into a genuine, ongoing email thread, usually via a compromised account, and replies with malicious content that inherits the thread''s established trust and context.",{"t":13,"text":14},"h2","Key facts",{"t":16,"items":17},"ul",[18,19,20],"It typically follows account takeover: the attacker replies from or spoofs a real participant inside a real conversation.","Because the thread, history and participants are genuine, recipients rarely suspect the injected reply.","It is a favored delivery method for BEC payment fraud and malware, precisely because the surrounding context does the persuasion.",{"t":13,"text":22},"How it works",{"t":10,"text":24},"An attacker compromises a mailbox, reads recent threads to understand who is discussing what, and picks a moment to reply, sometimes with new bank details, sometimes with a malicious link or attachment reframed as the deliverable everyone was waiting for. The quoted history sells it: the recipient sees their own earlier messages, the familiar participants, the expected topic. The reply looks like the next step in a conversation they trust.",{"t":13,"text":26},"Why it beats suspicion and filters",{"t":10,"text":28},"Traditional filters look for known-bad content and unusual senders; a hijacked reply comes from a real sender inside a real thread with passing authentication. There is nothing \"wrong\" at the surface layer. Only the behavior is wrong: an out-of-pattern change of bank details, an unusual link inside a thread that has never contained links, a document from a colleague who never shares that file type. This is the ground where business email compromise and vendor email compromise both thrive.",{"t":13,"text":30},"How to defend",{"t":10,"text":32},"Verify payment and link or attachment changes even within known threads, out of band and through a channel you control. Deploy phishing-resistant MFA to prevent the account takeover that makes hijacking possible in the first place. And add behavioral detection that recognizes out-of-pattern replies inside otherwise normal threads, the deviation is the signal.",{"t":13,"text":34},"How Sentaro helps",{"t":10,"text":36},"Sentaro''s Behavioral Defense models each organization''s real conversation graph and flags replies that break a thread''s established pattern: new payment instructions inside a routine relationship, first-ever attachments, tone shifts mid-thread. It also flags the account-takeover behavior that precedes hijacking, so the attack can be interrupted at both ends.",[38,41,44,47],{"q":39,"a":40},"What is thread hijacking in simple terms?","An attacker joins a real ongoing email conversation, usually because they have compromised one participant''s mailbox, and sends a reply that abuses the thread''s built-up trust to redirect payment, steal data or deliver malware.",{"q":42,"a":43},"How do attackers get into a real email thread?","Most often by account takeover (phishing, credential theft or AiTM), less often by careful spoofing where authentication and lookalike domains hide the substitution.",{"q":45,"a":46},"Why is thread hijacking so effective?","It inherits trust: the participants, history and topic are genuine, so the malicious reply reads as the next step in a conversation the recipient already believes in.",{"q":48,"a":49},"How do we detect thread hijacking?","Verify in-thread payment or link or attachment changes out of band, and use behavioral detection that flags replies breaking a thread''s established pattern rather than relying only on sender or content signals.","2026-09-08",[52,53,54,55,56],"account-takeover","aitm-phishing","business-email-compromise","phishing","vendor-email-compromise",[53,56,52,58],"consent-phishing",1789658071179]