EUVD-2025-202846

Comprehensive Technical Analysis of EUVD-2025-202846

1. Vulnerability Assessment and Severity Evaluation

The vulnerability described in EUVD-2025-202846 affects Sandboxie, a sandbox-based isolation software for Windows NT-based operating systems. The issue lies in the SYSTEM-level service SbieSvc.exe, which exposes SbieIniServer::RC4Crypt to sandboxed processes. The handler adds a fixed header size to a caller-controlled value_len without performing overflow checks. This can lead to a heap overflow when attacker data is copied into an undersized buffer, allowing sandboxed processes to execute arbitrary code as SYSTEM.

Severity Evaluation:

• Base Score: 9.9 (Critical)
• Base Score Version: 4.0
• Base Score Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:N

The high base score indicates a critical vulnerability due to the potential for complete system compromise with low attack complexity and no user interaction required.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Remote Exploitation: An attacker could exploit this vulnerability over the network by crafting malicious input that triggers the heap overflow.
• Local Exploitation: A local attacker with limited privileges could exploit this vulnerability to escalate privileges to SYSTEM.

Exploitation Methods:

• Heap Overflow: By sending a large value_len (e.g., 0xFFFFFFF0), an attacker can cause the allocation size to wrap, leading to a heap overflow.
• Arbitrary Code Execution: The heap overflow allows the attacker to execute arbitrary code with SYSTEM privileges, fully compromising the host.

3. Affected Systems and Software Versions

Affected Systems:

• Windows NT-based operating systems (32-bit and 64-bit)

Affected Software Versions:

• Sandboxie versions 1.16.6 and below

4. Recommended Mitigation Strategies

Immediate Mitigation:

• Upgrade: Upgrade to Sandboxie version 1.16.7 or later, which includes the fix for this vulnerability.
• Patch Management: Ensure that all systems running Sandboxie are regularly updated and patched.

Long-term Mitigation:

• Access Controls: Implement strict access controls to limit the exposure of critical services like SbieSvc.exe.
• Monitoring: Enhance monitoring and logging to detect and respond to suspicious activities related to sandboxed processes.
• Security Audits: Conduct regular security audits and vulnerability assessments to identify and mitigate similar issues.

5. Impact on European Cybersecurity Landscape

The vulnerability poses a significant risk to organizations and individuals using Sandboxie for sandbox-based isolation. Given the widespread use of Sandboxie in various sectors, including finance, healthcare, and government, the potential for widespread compromise is high. The European cybersecurity landscape could see increased incidents of privilege escalation and system compromise if this vulnerability is not promptly addressed.

6. Technical Details for Security Professionals

Vulnerability Details:

• Service: SbieSvc.exe
• Handler: SbieIniServer::RC4Crypt
• Issue: Lack of overflow checking when adding a fixed header size to value_len
• Consequence: Heap overflow leading to arbitrary code execution as SYSTEM

Exploitation Steps:

1. Craft Malicious Input: Create input with a large value_len to trigger the heap overflow.
2. Send Input: Send the crafted input to the SbieIniServer::RC4Crypt handler.
3. Execute Code: Exploit the heap overflow to execute arbitrary code with SYSTEM privileges.

References:

• GitHub Security Advisory
• GitHub Commit
• Sandboxie Release v1.16.7

Aliases:

• CVE-2025-64721

Assigner:

• GitHub_M

ENISA IDs:

• Product: Sandboxie (versions < 1.16.7)
• Vendor: sandboxie-plus

By addressing this vulnerability promptly and implementing robust mitigation strategies, organizations can significantly reduce the risk of exploitation and maintain the integrity of their systems.