Microsoft Patch Tuesday, September 2026 Security Update Review
Microsoft's September 2026 Patch Tuesday fixes 974 vulnerabilities, including 113 critical and two actively exploited Windows privilege escalation flaws.
Microsoft's September 2026 Patch Tuesday fixes 974 vulnerabilities, its largest release ever, including 113 critical and 860 important, covering Windows HTTP.sys, Hyper-V, Entra ID, Exchange Server, Office, DNS, and more. Two zero-days are confirmed exploited in the wild: CVE-2026-81963 (Windows Update Stack EoP) and CVE-2026-85880 (ALPC heap overflow), both letting authenticated attackers gain SYSTEM privileges. Notable criticals include an Entra ID authentication bypass (CVE-2026-62916) and multiple Windows DNS Server and Office remote code execution flaws.
Off Guard: Breaking LiteLLM from authentication bypass to cloud compromise
Wiz found LiteLLM auth bypass (CVE-2026-59822) and post-auth RCE (CVE-2026-59821) chainable to cloud compromise; the bypass is in CISA KEV with in-the-wild exploitation.
Wiz scanned roughly 3,074 internet-facing LiteLLM deployments and found 9.6% accepted the default master key sk-1234 or required no authentication, making post-auth attacks effectively pre-auth. The MCP endpoint accepts any Bearer token and grants a valid session (CVE-2026-59822), confirmed exploited in the wild via honeypots and added to CISA's Known Exploited Vulnerabilities catalog. Custom code guardrails allow post-auth root-level RCE via exec(compile(...)) (CVE-2026-59821), while pass-through endpoints lack URL validation, enabling cloud credential theft in post-auth scenarios. All assigned vulnerabilities have been patched; the research was presented at DEF CON 34.
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.
BigBear 2.0 phishing campaign hijacks Microsoft 365 sessions after MFA
CloudSEK uncovered BigBear 2.0, a PhaaS operation that captured 4,148 Microsoft 365 session cookies, hijacking authenticated sessions after MFA via AiTM proxy.
CloudSEK infiltrated the BigBear 2.0 phishing-as-a-service panel in June, finding 5,137 credential records tied to 461 organizations in over 40 countries, including 4,148 captured session cookies and 474 completed post-MFA logins. The operation, built on Evilginx2, uses an attacker-controlled reverse proxy to steal authenticated session cookies and residential proxies to defeat location-based Conditional Access checks, while custom code disables FIDO2/WebAuthn on phishing pages. At least five affiliates operated 42 VPS nodes, with IT services and managed service providers the most targeted sector.
The Top 4 Threats We Found by Investigating Every Alert for a Quarter
Prophet Security's quarterly threat report finds identity attacks made up roughly half of confirmed malicious activity, with stolen authenticated sessions bypassing conditional access controls.
Between May 1 and July 31, 2026, Prophet Security investigated every alert in customer environments immediately on arrival; about 7% of completed investigations were confirmed malicious. Direct account/session attacks made up roughly 18% of confirmed activity, with replayed authenticated sessions bypassing conditional access since no re-authentication occurs. Infostealer activity affected about a quarter of investigated organizations, mostly delivered via browsers through compromised websites, malicious ads, sponsored search results and ClickFix fake CAPTCHA gates, with payloads including Lumma Stealer, Vidar, HijackLoader and AsyncRAT. Credential phishing was the largest category at about 28%, with adversary-in-the-middle relays revealed by seconds-long MFA approvals from distant countries and MFA fatigue attacks exploiting automatic unlock policies.
Passkey-themed phishing attacks lead to Microsoft 365 data theft
Microsoft links ShinyHunters- and Helix-affiliated actors to passkey-themed vishing and device-code phishing that compromises Microsoft 365 accounts and steals cloud data.
Microsoft attributes passkey- and SSO-themed social engineering activity, observed since May 2026, to Storm-3121 (linked to ShinyHunters and Falcon) and Storm-3032 (tied to BlackFile members now operating as Helix). Attackers impersonate corporate IT help desks by phone or SMS, urging fake passkey, MFA, or SSO updates and directing victims to adversary-in-the-middle phishing pages or device-code authentication flows that yield credentials, session tokens, and OAuth tokens. Post-compromise behavior includes Microsoft Graph enumeration of users, SharePoint, and OAuth grants, plus persistence via attacker-controlled MFA methods. Google Threat Intelligence tracks related activity as UNC6671, linked to the BlackFile, Helix, Falcon, Pink, and Redact extortion gangs.
BigBear Microsoft 365 phishing service bypassed MFA at 258 organizations
CloudSEK found the BigBear 2.0 phishing-as-a-service platform bypassed MFA at 258 organizations and captured over 5,000 Microsoft 365 credentials.
CloudSEK researchers gained administrator access to the BigBear 2.0 phishing-as-a-service control panel and found it had exfiltrated 5,137 credential records, including 474 completed MFA-bypassed authentications, 1,032 plaintext passwords, and 4,148 session cookies across 3,331 victim IPs in 40+ countries. The Evilginx2-based AitM proxy intercepts credentials and authenticated session cookies, and custom JavaScript interferes with FIDO2/WebAuthn to force weaker authentication. The panel is leased to at least five affiliate operators via Telegram exfiltration bots, and geo-matched residential proxies cover 69 countries to evade detection.
Critical NetScaler Flaw Can Bypass Authentication on Certain Gateway and AAA Servers
Citrix patches critical NetScaler Gateway and AAA authentication bypass CVE-2026-19490 (CVSS 9.3) plus a SIP ALG memory overflow flaw; exploitation attempts observed.
Citrix fixed CVE-2026-19490 (CVSS 9.3), an authentication bypass affecting customer-managed NetScaler ADC and Gateway appliances configured as Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy) or AAA virtual servers, and CVE-2026-19489 (CVSS 8.8), a memory overflow causing DoS when SIP ALG is enabled in Large Scale NAT groups. Updates are available in versions 14.1-73.32, 13.1-63.21, and corresponding FIPS/NDcPP builds, while Citrix-managed cloud services were already patched. The flaws were reported by Samarth Vashisht of JPMorgan Chase's penetration-testing team, and Previdian later observed 10 exploitation attempts against CVE-2026-19490 from six unique IP addresses in Australia, Germany, Japan, and the US, with no confirmed compromise.
Suspected Russian Hackers Abuse Google OAuth and WhatsApp Linking to Hijack Accounts
Google tracked three suspected Russian espionage clusters abusing OAuth flows, app passwords, and WhatsApp linking to hijack accounts of diplomats and defense targets.
Google Threat Intelligence Group detailed three suspected Russian espionage clusters, UNC6293, UNC7005 (Storm-2945), and UNC5976, targeting academia, aerospace, defense, governments, and think tanks in Europe, the US, Ukraine, and Armenia. UNC6293, assessed as a sub-cluster of APT29/Ice Relic, conducted OAuth and application-specific password phishing while impersonating State Department officials. UNC5976 registered file-sharing-themed domains hosting fake OAuth login pages and deployed a malicious Excel plugin codenamed HEADRUSH, while UNC7005 abused WhatsApp device linking to hijack accounts and record victims' audio and video.
CVE-2026-16232: Check Point SmartConsole Auth Bypass
Check Point SmartConsole authentication bypass CVE-2026-16232 grants unauthenticated attackers full admin access; actively exploited and added to CISA KEV.
CVE-2026-16232 is an improper authentication flaw (CWE-287) in the Check Point SmartConsole login process that lets an unauthenticated remote attacker obtain an application token and authenticate with full administrative privileges. Exploitation requires the Management Server to be internet-reachable and the Trusted Clients list not restricted to specific administrator addresses. Check Point confirmed active exploitation affecting a small number of customers, and the vulnerability has been added to the CISA Known Exploited Vulnerabilities catalog. A hotfix is available via Check Point advisory sk185169.
Hackers Compromised 14,500+ Dahua Devices Using Credential Attacks, Auth Bypasses, and P2P
Hunt.io disclosed Operation CameraSwarm, compromising 14,500+ Dahua cameras via credential attacks, auth bypass CVEs, and P2P relay techniques across Ukraine and Russia.
Hunt.io reconstructed a campaign codenamed Operation CameraSwarm that compromised over 14,530 Dahua devices between June 17 and July 22, 2026. Attack paths included credential attacks against 12,324 IPs, exploitation of CVE-2021-33044 and CVE-2021-33045 affecting 1,923 cameras, and P2P relay access to 283 devices behind NAT. The operator, assessed as Russian-speaking, left behind 2,616 files including tooling and campaign logs, with confirmed compromises concentrated in Ukraine and Russia. Dahua advises factory resets and firmware updates; both 2021 CVEs remain in CISA's KEV catalog.
BigBear phishing crew nets thousands of Microsoft 365 credentials
CloudSEC accessed the BigBear 2.0 phishing panel, finding 5,137 stolen Microsoft 365 records across 461 organizations, including 474 MFA-bypassed sessions.
CloudSEC researchers got inside the admin panel of BigBear 2.0, an Evilginx2-based phishing-as-a-service operation run by someone known as 'General Boss'. The panel contained 5,137 records tied to 461 organizations: 1,032 plaintext passwords and 4,148 session cookies, with 474 complete MFA-bypassed authentications. The adversary-in-the-middle proxy captures Microsoft 365 session cookies that can be replayed to access email, Teams, SharePoint, and OneDrive, potentially pivoting into Entra ID and federated SaaS. The operation was still active, used custom JavaScript to disable FIDO2/WebAuthn on phishing pages, and routed logins through a residential proxy pool spanning 69 countries.
Inside Operation CameraSwarm: How One Actor Took Over 14,000 Dahua Cameras
One actor compromised over 14,000 Dahua cameras in Ukraine and Russia using brute-force, authentication bypass, and cloud relay serial-number abuse.
Hunt.io reconstructed Operation CameraSwarm from an exposed operator directory, revealing one actor compromised 14,000+ Dahua cameras between June 17 and July 22, 2026, mainly in Ukraine and Russia. The toolkit included a brute-force engine, a two-flaw 2021 authentication-bypass chain planting a persistent backdoor account on 1,923 cameras, and abuse of Dahua's cloud relay where 89.4% of probed serials returned open, unauthenticated channels. A SalatStealer Windows binary and Defender-disabling PowerShell script were staged on the same server but appear unrelated to the camera campaign.