M365 Copilot Business Chat SearchLeak Open-Redirect Prompt-Injection Exfil (CVE-2026-47645) - ATR-2026-01957 (f29175c6-d796-5599-a5bf-d0c31a98c06b)
Detects the SearchLeak one-click exploitation associated with CVE-2026-47645 (open redirect / elevation of privilege in Microsoft 365 Copilot Business Chat). An attacker delivers a link to the trusted m365.cloud.microsoft/search/ endpoint with attacker instructions packed into the q= parameter (parameter-to-prompt injection); Copilot acts with the victim's privileges and exfiltrates mailbox/file data through a Bing image-proxy SSRF sink (searchbyimage?cbir=sbi&imgurl=attacker). This rule keys on that specific endpoint+q-injection link and the Bing image-search exfiltration sink, not on bare Microsoft or Bing URLs.