Cybercriminals are building phishing pages that exist only inside victims’ browsers
Barracuda details a DocuSign-themed phishing campaign that renders login pages locally via blob URLs, abusing genuine Microsoft OAuth and Teams infrastructure.
Barracuda researchers describe a phishing campaign that starts with DocuSign-themed emails carrying calendar invites pointing to genuine Microsoft OAuth endpoints, then routes victims through Microsoft Teams to a resource hosted on cdn.bloom[.]io. The login page is assembled entirely inside the victim's browser from a blob URL, registers a service worker, and runs inside a sandboxed iframe that receives live instructions from the attacker's backend. Hidden command-and-control configuration indicates the page is part of a centrally managed phishing platform that can be updated and steered across many victims. Barracuda recommends phishing-resistant MFA such as FIDO2 keys or passkeys, monitoring of OAuth flows and redirect chains, and behavior-based identity controls rather than URL blocklisting.
Hackers Use Blob URLs and Microsoft Teams to Create Phishing Pages Inside Victims’ Browsers
Barracuda details a phishing campaign using Microsoft Teams OAuth redirects and browser blob URLs to render local fake DocuSign login pages for credential theft.
Barracuda researchers identified an active phishing campaign that routes DocuSign-themed emails with calendar invites through a Microsoft OAuth endpoint and crafted redirects into Microsoft Teams, then renders a fake sign-in page via a browser-generated blob URL. Because the page is assembled locally in memory and can register service workers and run in a sandboxed iframe, URL-reputation checks largely see legitimate Microsoft domains. The goal is credential theft and account takeover, not a flaw in Teams itself.
ZDI-26-629: Microsoft Azure Entra ID OAuth Device Code Grant Information Disclosure Vulnerability
Zero Day Initiative disclosed an unauthenticated information disclosure vulnerability (CVSS 5.8) in Microsoft Azure Entra ID's OAuth device code grant flow.
ZDI published advisory ZDI-26-629 describing an information disclosure vulnerability in Microsoft Azure Entra ID related to the OAuth device code grant. Remote attackers can disclose sensitive information without authentication. ZDI assigned a CVSS 3.1 score of 5.8; no CVE identifier is listed in the advisory text.
NovaCookies Campaigns Abuse Genuine Docusign Notifications to Steal Microsoft 365 Sessions
NovaCookies AitM phishing kit, a Sneaky 2FA variant, uses genuine Docusign lures to steal Microsoft 365 sessions at hundreds of organizations.
Island disclosed NovaCookies, a $320/month adversary-in-the-middle phishing-as-a-service platform that relays Microsoft 365 sign-ins through attacker infrastructure to capture credentials, MFA codes, and authenticated sessions. Campaigns abuse genuine Docusign envelopes and Microsoft/Google redirect hops so each step looks legitimate, with lure domains on .vu and alternating-case labels such as PwPt-sHaRe. Proofpoint assesses NovaCookies as a Sneaky 2FA variant with added flows for Okta and Entra domains federated to GoDaddy, and a fully managed PhaaS model. It has targeted hundreds of organizations in the U.S., U.K., Canada, Germany, Israel, and the U.A.E., and is advertised via Telegram with anti-analysis checks like a Cloudflare gate.