Beyond RC4 for Windows authentication
Microsoft outlined its transition plan to move away from RC4 for authentication and published guidance and tools to facilitate this change.
https://www.microsoft.com/en-us/windows-server/blog/2025/12/03/beyond-rc4-for-windows-authentication
FortiCloud SSO Login Vuln Exploited
Arctic Wolf observed exploit attempts against vulnerable FortiGate appliances.
https://arcticwolf.com/resources/blog/arctic-wolf-observes-malicious-sso-logins-following-disclosure-cve-2025-59718-cve-2025-59719/
FrePBX Vulnerability
Horizon3.ai identified three distinct vulnerabilities in FreePBX. In particular, the authentication by-pass issue should be of concern, but default FreePBX installs do not use the vulnerable web authentication feature.
https://horizon3.ai/attack-research/the-freepbx-rabbit-hole-cve-2025-66039-and-others/

More React2Shell Exploits CVE-2025-55182
Our honeypots continue to detect numerous React2Shell variants. Some using slightly modified exploits
https://isc.sans.edu/diary/More%20React2Shell%20Exploits%20CVE-2025-55182/32572
The Fragile Lock: Novel Bypasses For SAML Authentication
SAML is a tricky protocol to implement correctly, in particular if different XML parsers are used that may not always agree on how to parse a specific message
https://portswigger.net/research/the-fragile-lock
December Updates Causes issues with Microsoft Message Queuing
https://learn.microsoft.com/en-us/windows/release-health/status-windows-10-22h2#message-queuing--msmq--might-fail-with-the-december-2025-windows-security-update

Abusing DLLs EntryPoint for the Fun
DLLs will not just execute code when some of their functions are called, but also as they are loaded.
https://isc.sans.edu/diary/Abusing%20DLLs%20EntryPoint%20for%20the%20Fun/32562
Apple Patches Everything: December 2025 Edition
Apple released patches for all of its operating systems, fixing two already exploited vulnerabilities.
ClickFix Attacks Still Using the Finger
ClickFix Attacks Still Using the Finger
Two examples of ClickFix attacks abusing the finger protocol to load additional malware
Denial of Service and Source Code Exposure in React Server Components
Denial of Service and Source Code Exposure in React Server Components
After last week's critical patch, three more, but less critical, vulnerabilities were identified in React Server Components.
https://react.dev/blog/2025/12/11/denial-of-service-and-source-code-exposure-in-react-server-components

Using AI Gemma 3 Locally with a Single CPU
Installing AI models on modes hardware is possible and can be useful to experiment with these models on premise
https://isc.sans.edu/diary/Using%20AI%20Gemma%203%20Locally%20with%20a%20Single%20CPU%20/32556
Mystery Google Chrome 0-Day Vulnerability
Google released an update for Google Chrome fixing a vulnerability that is already being exploited, but has not CVE number assigned to it yet
https://chromereleases.googleblog.com/2025/12/stable-channel-update-for-desktop_10.html
SOAPwn: Pwning NET Framework Applications Through HTTP Client Proxies And WSDL
Watchtwr identified a common vulnerability in SOAP implementations using .Net
https://labs.watchtowr.com/soapwn-pwning-net-framework-applications-through-http-client-proxies-and-wsdl/

Possible exploit variant for CVE-2024-9042 (Kubernetes OS Command Injection)
We observed HTTP requests with our honeypot that may be indicative of a new version of an exploit against an older vulnerability. Help us figure out what is going on.
https://isc.sans.edu/diary/Possible%20exploit%20variant%20for%20CVE-2024-9042%20%28Kubernetes%20OS%20Command%20Injection%29/32554
React2Shell: Technical Deep-Dive & In-the-Wild Exploitation of CVE-2025-55182
Wiz has a writeup with more background on the React2Shell vulnerability and current attacks
https://www.wiz.io/blog/nextjs-cve-2025-55182-react2shell-deep-dive
Notepad++ Update Hijacking
Notepad++ s vulnerable update process was exploited
https://notepad-plus-plus.org/news/v889-released/
New macOS PackageKit Privilege Escalation
A PoC was released for a new privilege escalation vulnerability in macOS. Currently, there is no patch.
https://khronokernel.com/macos/2024/06/03/CVE-2024-27822.html

Microsoft Patch Tuesday
Microsoft released its regular monthly patch on Tuesday, addressing 57 flaws.
https://isc.sans.edu/diary/Microsoft%20Patch%20Tuesday%20December%202025/32550
Adobe Patches
Adobe patched five products. The remote code execution in ColdFusion, as well as the code execution issue in Acrobat, will very likely see exploits soon.
https://helpx.adobe.com/security.html
Ivanti Endpoint Manager Patches
Ivanti patched four vulnerabilities in End Point Manager.
https://forums.ivanti.com/s/article/Security-Advisory-EPM-December-2025-for-EPM-2024?language=en_US
Fortinet FortiCloud SSO Vulnerability
Due to a cryptographic vulnerability, Forinet s FortiCloud SSO authentication is bypassable.
https://fortiguard.fortinet.com/psirt/FG-IR-25-647
ruby-saml vulnerability
Ruby fixed a vulnerability in ruby-saml. The issue is due to an incomplete patch for another vulnerability a few months ago.
https://github.com/SAML-Toolkits/ruby-saml/security/advisories/GHSA-9v8j-x534-2fx3

nanoKVM Vulnerabilities
The nanoKVM device updates firmware insecurely; however, the microphone that the authors of the advisory referred to as undocumented may actually be documented in the underlying hardware description.
https://www.tomshardware.com/tech-industry/cyber-security/researcher-finds-undocumented-microphone-and-major-security-flaws-in-sipeed-nanokvm
Ghostframe Phishing Kit
The Ghostframe phishing kit uses iFrames and random subdomains to evade detection
https://blog.barracuda.com/2025/12/04/threat-spotlight-ghostframe-phishing-kit
WatchGuard Advisory
WatchGuard released an update for its Firebox appliance, fixing ten vulnerabilities. Five of these are rated as High.
https://www.watchguard.com/wgrd-psirt/advisories

AutoIT3 Compiled Scripts Dropping Shellcodes
Malicious AutoIT3 scripts are usign the FileInstall function to include additional scripts at compile time that are dropped as temporary files during execution.
https://isc.sans.edu/diary/AutoIT3%20Compiled%20Scripts%20Dropping%20Shellcodes/32542
React2Shell Update
The race is on to patch vulnerable systems. Various groups are aggressively scanning the internet with different exploit variants. Some attempt to bypass WAFs.
https://blog.cloudflare.com/5-december-2025-outage/
https://aws.amazon.com/blogs/security/china-nexus-cyber-threat-groups-rapidly-exploit-react2shell-vulnerability-cve-2025-55182/
Apache Tika XXE Flaw
Apache s Tika library patched a XXE flaw.
https://lists.apache.org/thread/s5x3k93nhbkqzztp1olxotoyjpdlps9k

Nation-State Attack or Compromised Government? [Guest Diary]
An IP address associated with the Indonesian Government attacked one of our interns' honeypots.
https://isc.sans.edu/diary/Nation-State%20Attack%20or%20Compromised%20Government%3F%20%5BGuest%20Diary%5D/32536
React Update
Working exploits for the React vulnerability patched yesterday are not widely available
Array Networks Array AG Vulnerablity
A recently patched vulnerability in Array Networks Array AG VPN gateways is actively exploited.
https://www.jpcert.or.jp/at/2025/at250024.html

Attempts to Bypass CDNs
Our honeypots recently started receiving scans that included CDN specific headers.
https://isc.sans.edu/diary/Attempts%20to%20Bypass%20CDNs/32532
React Vulnerability CVE-2025-55182
React patched a critical vulnerability in React server components. Exploitation is likely imminent.
https://react.dev/blog/2025/12/03/critical-security-vulnerability-in-react-server-components
Unveiling 3 PickleScan Vulnerabilities
The PyTorch AI model security tool, PickleScan, has patched three critical vulnerabilities.
https://jfrog.com/blog/unveiling-3-zero-day-vulnerabilities-in-picklescan/