Overview
A critical vulnerability has been identified in Quark Cloud Drive version 3.23.2, tracked as CVE-2025-63685. This vulnerability is classified as a DLL hijacking issue, stemming from the application’s insecure method of loading system libraries. This blog post provides a detailed analysis of the vulnerability, its potential impact, and steps to mitigate the risk.
Technical Details
Quark Cloud Drive v3.23.2 is vulnerable to DLL hijacking due to its failure to properly validate the path and signature of `regsvr32.exe` during the loading of system libraries. Specifically, the application attempts to load `regsvr32.exe` without verifying its authenticity or location. This creates an opportunity for attackers to exploit this weakness. By placing a malicious DLL with a carefully chosen name in the same directory from which Quark Cloud Drive is launched, an attacker can trick the application into loading and executing their malicious code when the application starts. This effectively allows the attacker to execute arbitrary code with the same privileges as the user running Quark Cloud Drive.
CVSS Analysis
At the time of writing, the CVSS score for CVE-2025-63685 is not available (N/A). However, given the potential for arbitrary code execution, it is likely to be assessed as High or Critical once a score is assigned.
Possible Impact
The successful exploitation of this DLL hijacking vulnerability can have severe consequences, including:
- Arbitrary Code Execution: Attackers can execute malicious code on the victim’s system with the privileges of the user running Quark Cloud Drive.
- Data Theft: Sensitive data stored within Quark Cloud Drive or accessible through the user’s account can be stolen.
- System Compromise: The attacker can gain full control of the compromised system, potentially leading to further attacks on the network.
- Malware Installation: The attacker can install malware, such as ransomware or keyloggers, on the victim’s system.
Mitigation and Patch Steps
To mitigate the risk posed by CVE-2025-63685, the following steps are recommended:
- Upgrade to a patched version: The most effective solution is to upgrade Quark Cloud Drive to a version that addresses this vulnerability. Check the vendor’s website for updates.
- Temporary Workaround (If no patch is available): As a temporary workaround, avoid running Quark Cloud Drive from directories with write access for untrusted users. This will prevent attackers from placing malicious DLLs in the application’s startup directory.
- Implement Application Control: Use application control software to restrict which applications and DLLs are allowed to run on the system.
- User Awareness: Educate users about the risks of running applications from untrusted sources and the importance of keeping their software up-to-date.
