New Passkey Attacks Can Recover Synced Private Keys or Bypass Phishing
Three research teams showed passkey bypasses: WebAuthn assertion replay in Microsoft Entra ID, synced-passkey key recovery in Google Password Manager, and Windows Hello key reuse.
SpecterOps' Pass-the-Passkey research showed Windows stored past YubiKey signatures in cleartext and chained this with Microsoft Entra ID passkey validation weaknesses to impersonate privileged users despite phishing-resistant MFA; the Windows Event Logging Service issue is tracked as CVE-2026-34348 (CVSS 6.5) and fixed in July 2026 updates. Unit 42's Golden Pass-ta-key attack recovered the 32-byte Security Domain Secret protecting Google Password Manager synced passkeys from Chrome on Windows via pre-existing malware. Dirk-jan Mollema showed in-session malware can use a hardware-bound Windows Hello for Business key without a fresh PIN or biometric check. Microsoft applied Entra-side mitigations for the relay assertion issue; no real-world exploitation has been reported.
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.
Inside Knight Office, a New M365 AiTM Phishing Kit
Huntress details Knight Office, a new AiTM phishing kit stealing Microsoft 365 session tokens and registering attacker-controlled devices.
Huntress investigated an August 18, 2026 adversary-in-the-middle attack using the Knight Office phishing kit, which captured Microsoft 365 session tokens via a DocuSign-style lure routed through a Monday.com tracking link and a compromised Joomla site. After token capture, the actor enrolled an unauthorized host in Microsoft Entra ID and bound a Windows Hello for Business key credential to the account. The kit's operator console, found at IP 104.37.188.94, is built on Python Flask and hosts at least 25 .vu phishing domains. Telemetry links the kit to at least nine token-replay logins in two weeks and roughly 700 reported lure emails since April.
Risky Bulletin: Expired cards can be used for new transactions
Researchers show expired Visa contactless cards can be revived via NFC man-in-the-middle relay to run fraudulent transactions; roundup also covers major breaches.
University of Massachusetts Amherst researchers built an NFC man-in-the-middle rig that updates a card's expiration date in transit and relays the modified payment to POS terminals, reviving expired contactless cards; Visa terminals and the backends of all five banks studied failed to catch the manipulation. The same roundup reports Iranian hackers shut down a small UK power plant for four days, Lazarus breached South Korea's Presidential Office as part of a campaign exceeding 100 victims, and French telecom SFR suffered a breach affecting over 2.1 million customers.
Cavern C2 Uses DNS and Google Apps Script to Blend Into Legitimate Traffic
Kaspersky details Iranian Cavern Manticore's expanded C2 framework using DNS and Google Apps Script, plus APT42's TAMECAT spyware in nuclear-sector phishing.
Kaspersky reported new components in the Cavern (Cav3rn) C2 framework, used by Iranian MOIS-affiliated Cavern Manticore (with overlaps to MuddyWater and OilRig's Lyceum) against Israeli entities, monitored since December 2025. The new GoogleService.dll module performs DNS A-record queries to choose between direct HTTPS and a Google Apps Script relay per transaction, with the DNS infrastructure able to rotate the Google deployment ID; Kaspersky also found an inter-component broker (rnp.dll) and linked the framework's plugin-based pivot to late April 2026. Separately, Group-IB and Kaspersky detailed HOLLOWGRAPH, a .NET NativeAOT DLL first seen in the wild June 7, 2026, that uses Microsoft 365 calendar events via the Graph API as two-way dead drops dated May 13, 2050, with DNS tunneling refreshing Entra ID credentials. DarkAtlas also reported APT42's TAMECAT modular surveillance framework delivered via LNK masquerading as PDFs in spear-phishing targeting the nuclear energy sector in April-May 2026, with the group using generative AI to accelerate operations.
Jenkins security advisory (AV26-877)
Canada's Cyber Centre relayed a Jenkins advisory (AV26-877) covering core and numerous plugin vulnerabilities fixed in 2.568.3/2.580.
The Canadian Centre for Cyber Security published advisory AV26-877 for the Jenkins security advisory dated September 2, 2026. Affected products include Jenkins releases other than 2.568.3 and 2.580, plus plugins such as GitLab, LDAP, Microsoft Entra ID, SAML, Script Security, Pipeline Build Step, and others. Administrators are encouraged to review the linked advisory and apply necessary updates.