Skip to main content
Meet us at Black Hat USA 2026— Las Vegas, August 1–6Book a Meeting
Mallory
MediumPublic exploit

Arbitrary Process Termination in Tower of Fantasy GameDriverX64.sys

IdentifiersCVE-2025-61155CWE-284

GameDriverX64.sys, the Tower of Fantasy anti-cheat kernel-mode driver, version 7.23.4.7 and earlier, contains an access control flaw in an IOCTL handler. A user-mode process can open a handle to the device object exposed by the driver and issue specially crafted IOCTL requests that are executed in kernel context without proper authentication or authorization checks. As described in the provided content, this allows an unprivileged local attacker to invoke driver functionality to terminate arbitrary processes, including security products and critical system services, from kernel mode.

Share:
For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows a local unprivileged attacker to kill arbitrary processes in kernel context. In practice, this can be used to disable EDR, AV, and other security tooling, terminate critical Windows services, and materially weaken host defenses prior to follow-on activity such as credential theft, lateral movement, persistence, or ransomware deployment. The content specifically notes abuse in BYOVD scenarios to terminate security software before encryption.

Mitigation

If you can’t patch tonight, do this now.

Prevent untrusted or unnecessary kernel drivers from being loaded, including renamed copies of GameDriverX64.sys such as UpdateCheckerX64.sys noted in the content. Enable and enforce Microsoft vulnerable driver blocklist protections and HVCI/Memory Integrity where operationally feasible. Use application control/WDAC policies to restrict driver installation and loading, monitor for suspicious driver loads and device-handle access to the driver, and alert on attempts to terminate security processes from kernel context. Restrict local code execution opportunities for unprivileged users to reduce exploitability.

Remediation

Patch, then assume compromise.

Update or replace GameDriverX64.sys with a fixed version newer than 7.23.4.7 if available from the vendor. Remove the vulnerable driver from systems where it is not strictly required. Because the driver has been abused in BYOVD attacks, organizations should also block loading of the known vulnerable binary and any renamed copies, and ensure vulnerable-driver block policies are enforced where supported.
PUBLIC EXPLOITS

Exploits

1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos (1 hidden).

VALID 1 / 2 TOTALView more in app
CVE-2025-61155MaturityPoCVerified exploit

This repository is a real exploit-focused research repo for CVE-2025-61155, not just a README. It documents and demonstrates a local BYOVD-style abuse path in the signed Windows anti-cheat driver GameDriverX64.sys used by Tower of Fantasy. The core exploit capability is arbitrary process termination from kernel context: an unprivileged local process can satisfy the driver's weak create-time gate by loading any DLL named QmGUI.dll, QmGUI4.dll, or gameuirender.dll, then open the exposed device \\.\HtAntiCheatDriver and send IOCTL 0x222040 with an 8-byte buffer containing magic 0xFA123456 and a target PID. The driver then performs ZwOpenProcess(GENERIC_ALL) and ZwTerminateProcess in kernel mode, allowing termination of arbitrary processes including protected AV/EDR services. Repository structure is primarily documentation-heavy, with one actual PoC source file and one YARA detection ruleset. Key files are: poc/poc.cpp (minimal C++ PoC and main entry point), advisory.md (formal advisory), docs/01-technical-analysis.md (reverse-engineering teardown of the driver internals and exploit chain), docs/02-exploitation.md (walkthrough of the abuse flow), docs/03-detection.md and detection/* (YARA and IOC content), docs/04-mitigation.md (blocklist/WDAC guidance), and docs/05-in-the-wild.md (threat-actor usage context). The vulnerable driver binary itself is intentionally omitted; sample/SAMPLE.md provides hashes, signer, and provenance instead. The PoC is operational but basic rather than weaponized: it defaults to targeting notepad.exe, uses hardcoded constants, and does not include driver installation or advanced targeting logic. Still, it clearly demonstrates the exploit chain and the main offensive outcome: local disabling of security tooling via a vulnerable signed driver already reported as abused in the wild.

sys0xFFDisclosed Jun 25, 2026cppyaralocal
What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence9

Every observed campaign linking this CVE to a named adversary.

Associated malware20

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity4

Community discussion across Reddit, Mastodon, and other social sources.