Researchers have detailed a cyber-espionage campaign in which attackers maintained access to a global stock exchange executive's Microsoft Outlook mailbox for roughly five months. The intrusion relied on a malicious OAuth application and inbox-rule persistence to quietly read and forward mail while evading detection. By abusing OAuth consent rather than stealing a password, the attackers retained access that survived password changes and looked like routine application traffic in logs. The five-month dwell time on a single high-value executive points to a patient, intelligence-driven operation rather than opportunistic crime. The case reinforces the now-recurring pattern of OAuth-app abuse and malicious inbox rules as the core of stealthy Microsoft 365 mailbox compromise.
Follow-up: this is the origin-story update to the Vercel breach disclosed April 19 (which our publication did not cover at the time). Hudson Rock traced the initial compromise to a Context.ai employee whose laptop was infected by Lumma Stealer malware in February 2026 after the user downloaded Roblox 'auto-farm' scripts and game-exploit executors - a notorious delivery vector for infostealers. The malware harvested that employee's Google Workspace credentials plus access keys and logins for Supabase, Datadog, and Authkit. The haul also included the support@context.ai account, letting the attacker escalate inside Context.ai, reach its AWS environment, and then pivot through compromised Google Workspace OAuth tokens into a Vercel employee's enterprise workspace that had granted the 'AI Office Suite' app 'Allow All' permissions. The attacker (ShinyHunters, now selling the data for $2M on BreachForums) read Vercel environment variables not flagged as 'sensitive.' Google pulled the Context.ai Chrome extension (ID omddlmnhcofjbnbflmjginpjjblphbgk) on March 27 - it embedded an OAuth grant for read access to users' entire Google Drive. The lesson is brutal: one employee's personal risky behavior on a work device cascaded through four SaaS platforms into a supply-chain breach that a threat actor is now auctioning.
TrustStrike Labs