ToolPublished 4 Jun 2026

LSASS/Defender/CTFMON analysis

Source Reddit BlueTeam

Discussion

Windows 11's input pipeline causes typed passwords from third-party applications like PuTTY, WinSCP, and MySQL to appear in system process memory such as LSASS.exe, Defender (MsMpEng.exe), and ctfmon.exe. This is due to Windows telemetry and text input buffering, not malicious credential harvesting. Passwords may remain in ctfmon.exe memory even after application closure, posing a risk if non-admin malware accesses that process. Credential Guard does not protect these third-party passwords as they are not Windows authentication credentials. This behavior is architectural and expected, not a vulnerability, but it creates a real risk of password exposure through memory forensics or malware. Mitigations include using secure credential APIs, key-based authentication, password managers with secure injection, and avoiding typing passwords into standard text input fields.

r/blueteamsec (opens in a new tab)u/H4x0rBattie0 points0 comments

Hi.

https://hexderef.com/windows-11-passwords-in-memory-lsass-ctfmon-analysis

Should it be a concern if another AV behaves like this? Definitely, especially if it transmits credentials over the network.

Links cited in the discussion

https://hexderef.com/windows-11-passwords-in-memory-lsass-ctfmon-analysis

Impact

Passwords typed into third-party applications may be exposed in memory of system processes such as LSASS.exe and ctfmon.exe. Non-admin malware could extract passwords from ctfmon.exe memory since it is not a protected process. Credential Guard does not protect these passwords, potentially leading to credential exposure if an attacker has local access or malware is present. LSASS memory dumps may contain non-Windows credentials, complicating incident response. However, no data exfiltration or keylogging APIs are involved, and this behavior is not considered a vulnerability by Microsoft. The risk is primarily from local memory access or malware with privilege escalation.

Defensive guidance

This behavior is considered expected and not a vulnerability by Microsoft. To mitigate risks: use secure credential APIs such as Windows Credential UI, Secure Desktop, Windows Hello, or Credential Manager; prefer key-based authentication methods (e.g., SSH keys) and disable password login where possible; avoid typing passwords into standard console or third-party application input fields; use password managers that support secure injection APIs; clear clipboard contents after use; and consider virtualization or dedicated jump hosts to isolate sensitive credential entry. Credential Guard should be enabled to protect Windows authentication secrets but does not protect third-party application passwords. These mitigations reduce exposure but do not eliminate the architectural behavior.

Summary

Windows 11 integrates multiple telemetry and input subsystems that buffer and analyze keyboard input for accessibility, diagnostics, and security. Typed passwords entered into third-party applications using standard Windows input APIs (e.g., PuTTY, WinSCP, MySQL CLI) can appear in LSASS.exe, ctfmon.exe, Microsoft Defender, and other processes due to shared input buffers and telemetry data flows. LSASS receives telemetry from ETW providers but does not actively read keystrokes. Passwords may remain in ctfmon.exe memory after application exit, which is not a protected process, allowing non-admin malware to potentially extract them. Credential Guard protects Windows authentication secrets but not these third-party passwords. This is a design limitation of Windows input architecture rather than a security vulnerability. Clipboard data can also appear in LSASS memory due to shared memory and secure desktop transitions. Mitigations focus on using secure credential APIs, key-based authentication, and avoiding insecure input methods.

References

Community reviews

Loading reviews…

Discussion

Links cited in the discussion

AI analysisMachine-generated, updated 4 Jun 2026, 13:33 UTC

Technical details

References

Community reviews

Related threats