Public Nightmare Eclipse PoCs Increase Risk to Endpoint Security Products 

Executive Summary

Security researchers operating under the Nightmare Eclipse / MSNightmare identity have recently published multiple proof-of-concept (PoC) exploits demonstrating security weaknesses in endpoint security products and privileged Windows components.

Recent disclosures include research affecting technologies associated with CrowdStrike Falcon, Kaspersky Endpoint Security, Avast/Gen Digital, Microsoft Defender, and NVIDIA components.

Several of the published PoCs demonstrate techniques that may abuse highly privileged security or system processes to perform attacker-influenced operations, including filesystem manipulation and writes to protected locations. In certain scenarios, successful exploitation may enable a locally authenticated or low-privileged user to escalate privileges to NT AUTHORITY\SYSTEM.

The public availability of exploit code increases the risk of secondary weaponization by threat actors, including incorporation into malware, post-exploitation frameworks, or hands-on-keyboard intrusion activity.

At the time of publication, the existence of a public PoC should not automatically be interpreted as evidence of widespread active exploitation. Organizations should differentiate between vulnerability disclosure, public exploit availability, and confirmed malicious exploitation.

Organizations using affected technologies are advised to validate vendor patches and mitigations, conduct targeted threat hunting, and review detection coverage for exploitation of privileged endpoint-security functionality.

Why This Matters

Endpoint Detection and Response (EDR) and antivirus products operate with extensive privileges to inspect, quarantine, modify, and remediate files across an endpoint.

These privileges can potentially become an attack surface when an attacker is able to influence the way a security product performs privileged operations.

The recent Nightmare Eclipse publications highlight a broader defensive concern:

User-controlled activity → manipulation of privileged security functionality → protected resource modification → potential privilege escalation

Public PoCs lower the technical barrier for other actors to study, modify, and potentially weaponize these techniques.

Published PoCs of Interest

FalconFlank — CrowdStrike Falcon

Risk: Local Privilege Escalation / Privileged File Operation Abuse

FalconFlank research reportedly demonstrates a potential privilege-escalation path involving CrowdStrike Falcon remediation functionality associated with suspicious or malicious Microsoft Office macro content. The technique involves manipulating filesystem behavior in a manner that may influence privileged security-agent file operations.

Successful exploitation may result in execution under:

PrettyPrague — Avast / Gen Digital

Risk: Privilege Escalation / Security Product Abuse

PrettyPrague is associated with research involving privileged functionality within Avast endpoint-security components.

The reported technique demonstrates how interactions with security-product functionality may potentially result in privileged execution.

Organizations using affected Avast/Gen Digital technologies should review current vendor guidance and investigate suspicious security-agent activity followed by unexpected SYSTEM-level execution or protected filesystem modifications.

HardBreacher / SolidSnake — Kaspersky Endpoint Security

Risk: Privilege Escalation / Privileged File Operation Abuse

HardBreacher and related research demonstrate potential abuse of privileged functionality associated with Kaspersky Endpoint Security.

The disclosed techniques involve manipulation of security-product file operations that may result in attacker-controlled content reaching protected Windows locations.

Organizations using Kaspersky Endpoint Security should verify that applicable vendor updates and mitigations have been deployed across their endpoint estate.

ShieldBreak — Microsoft Defender / Windows

Risk: Local Privilege Escalation / Privileged File Manipulation

ShieldBreak is associated with privilege-escalation research involving Microsoft Defender and privileged Windows functionality.

Related research demonstrates techniques that may influence privileged file operations and DLL placement, potentially enabling execution under SYSTEM privileges.

GreenSection — NVIDIA

Risk: Cross-User Memory Manipulation / Denial of Service

GreenSection research targets an NVIDIA shared-memory object and demonstrates a potential cross-user memory manipulation primitive.

The currently published research should not automatically be interpreted as demonstrating successful privilege escalation or remote-code execution unless additional evidence establishes such capability.

IOCs and Hunt Indicators

Files and Paths

  • FalconFlank.exe
  • PrettyPrague.exe
  • HardBreacher.exe
  • GreenSection.exe
  • C:\Windows\System32\WindowsPowerShell\v1.0\bcrypt.dll
  • C:\Windows\System32\phoneinfo.dll
  • C:\Windows\System32\MY_SNAKE_IS_SOLID.dll

Named Objects

  • FALCONFLANK
  • \BaseNamedObjects\{52813408-3561-4705-820a-2b3b78be92ba}

Scheduled Task

  • \Microsoft\Windows\Application Experience\MareBackup

SHA-256

  • c8c6f920d2b8b509425e909e8f1d0f4abfdc21eac6e532267ccb2578a9cdf97b

Recommended Actions

Organizations using the affected technologies should consider the following actions:

  1. Identify exposure — Determine whether CrowdStrike, Kaspersky, Avast/Gen Digital, Microsoft Defender, NVIDIA components, or other affected technologies are deployed within the environment.
  2. Review vendor guidance — Review the latest security advisories and technical notifications directly from affected vendors.
  3. Validate patch status — Confirm that applicable security-agent, operating-system, and driver updates have been deployed.
  4. Review mitigations — Apply vendor-recommended temporary mitigations where patches are not yet available.
  5. Conduct targeted threat hunting — Search for the PoC artifacts and behavioral patterns described in this advisory.
  6. Review EDR/AV telemetry — Identify unusual remediation activity involving protected Windows directories.
  7. Monitor filesystem manipulation — Detect suspicious reparse-point, junction, symbolic-link, and temporary-directory activity.
  8. Monitor privilege transitions — Investigate low-privileged activity immediately followed by unexpected SYSTEM-level execution.
  9. Review endpoint-security configuration — Identify unauthorized policy modifications, exclusions, disabled protections, or changes to remediation settings.
  10. Maintain heightened monitoring — Continue monitoring vendor advisories and threat-intelligence sources as the research evolves.

References

  • https://github.com/MSNightmare
  • https://github.com/MSNightmare/FalconFlank
  • https://github.com/MSNightmare/GreenSection
  • https://www.securityweek.com/nightmare-eclipse-drops-crowdstrike-nvidia-avast-zero-day-exploits/
  • https://www.bleepingcomputer.com/news/security/new-crowdstrike-falconflank-zero-day-grants-system-privileges/
  • https://thehackernews.com/2026/09/researcher-releases-falconflank-poc.html
  • https://www.theregister.com/security/2026/09/03/prolific-microsoft-0-day-hunter-drops-crowdstrike-falcon-exploit-poc/5294318
  • https://foresiet.com/blog/falconflank-crowdstrike-privilege-escalation-advisory/
  • https://detections.ai/share/inspiration/RZUL9VCI