CVE-2024-7238

Executive Summary

CVE-2024-7238 is a local privilege escalation vulnerability in VIPRE Advanced Security, specifically within the Anti Malware Service (SBAMSvc). The flaw allows an attacker with low-privileged code execution on the target system to abuse a symbolic link (symlink) following weakness to delete arbitrary files as the SYSTEM user. This can be leveraged to escalate privileges and execute arbitrary code in the SYSTEM context. The vulnerability has a CVSS score of 7.8 (High) and is classified under CWE-59 (Improper Link Resolution Before File Access). No public exploit code or proof-of-concept is currently available, and the vendor has not released a patch.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a local privilege escalation in a Windows-based security product (VIPRE Advanced Security). No supply chain implications are present.

CVSS Breakdown & Threat Level

• CVSS Score: 7.8 (High)
• Attack Vector: Local (AV:L)
• Attack Complexity: Low (AC:L)
• Privileges Required: Low (PR:L)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: High (C:H)
• Integrity Impact: High (I:H)
• Availability Impact: High (A:H)

The threat level is High due to the ability to escalate from low-privileged code to SYSTEM, enabling full system compromise.

Deep Dive & Mechanics

The vulnerability resides in the VIPRE Anti Malware Service (SBAMSvc.exe). The service performs file operations (specifically deletion) without properly validating symbolic links. An attacker who has already achieved low-privileged code execution can create a symbolic link pointing from a file the service intends to delete to a critical system file (e.g., C:\Windows\System32\config\SAM). When the service deletes the file, it follows the symlink and deletes the target, causing a denial of service or enabling further privilege escalation.

The attack flow:

1. Attacker gains low-privileged access (e.g., via phishing or another vulnerability).
2. Attacker identifies a file that the VIPRE service will delete (e.g., a quarantine file or temporary scan artifact).
3. Attacker creates a symbolic link from that file to a protected system file.
4. The VIPRE service, running as SYSTEM, deletes the file, following the symlink and deleting the target.
5. Attacker leverages the deletion to cause a system crash, replace a service binary, or otherwise escalate to SYSTEM.

Vulnerable vs. Patched Code

No patched code is available. The vulnerable code likely involves a DeleteFile or MoveFile call without using NtCreateFile with the FILE_OPEN_REPARSE_POINT flag or checking for symbolic links. A patched version would use CreateFile with FILE_FLAG_OPEN_REPARSE_POINT to prevent following symlinks, or validate the target path before deletion.

Vulnerable (pseudocode):

// Vulnerable: follows symlinks
DeleteFileW(targetPath);

Patched (pseudocode):

// Patched: opens file without following symlinks
HANDLE hFile = CreateFileW(targetPath, DELETE, 0, NULL, OPEN_EXISTING, FILE_FLAG_OPEN_REPARSE_POINT, NULL);
if (hFile != INVALID_HANDLE_VALUE) {
    // Check if it's a symlink
    if (GetFileInformationByHandleEx(hFile, FileStandardInfo, ...)) {
        // If symlink, abort
    } else {
        DeleteFileW(targetPath);
    }
    CloseHandle(hFile);
}

Exploitation & Lab Setup

Red Team

Prerequisites:

• Low-privileged code execution on a Windows system with VIPRE Advanced Security installed.
• Knowledge of a file path that the VIPRE service will delete (e.g., quarantine directory).

Exploitation Steps:

1. Identify a file that VIPRE will delete (e.g., a quarantined file in C:\ProgramData\VIPRE\Quarantine\).
2. Create a symbolic link from that file to a target (e.g., C:\Windows\System32\drivers\etc\hosts).

   mklink C:\ProgramData\VIPRE\Quarantine\malware.exe C:\Windows\System32\drivers\etc\hosts
   

3. Trigger the VIPRE service to delete the quarantined file (e.g., by initiating a scan or manual cleanup).
4. The service deletes the target file as SYSTEM, causing a denial of service or enabling further exploitation.

Note: No public exploit code exists. This is a theoretical exploitation based on the vulnerability description.

Blue Team

Detection:

• Monitor for symbolic link creation events (Event ID 4663 with access mask 0x1 for symlink creation).
• Monitor for file deletion events by the VIPRE service (Event ID 4663 with DELETE access).
• Look for unusual file paths being deleted by SBAMSvc.exe.

Hunting:

• Search for symlinks pointing to critical system files.
• Use Sysmon to log process creation and file deletion events.

Indicators of Compromise (IOCs)

• Process: SBAMSvc.exe performing file deletion on unexpected paths.
• File: Symbolic links created in VIPRE quarantine directories pointing to system files.
• Registry: N/A
• Network: N/A (local vulnerability)

Detection Engineering

YARA Rule

rule CVE_2024_7238_Symlink_Abuse {
    meta:
        description = "Detects symbolic link creation targeting VIPRE quarantine files"
        author = "Valters IT"
        date = "2025-01-01"
        reference = "CVE-2024-7238"
    strings:
        $symlink_cmd = "mklink" nocase
        $vipre_path = "VIPRE" nocase
        $quarantine = "Quarantine" nocase
    condition:
        $symlink_cmd and $vipre_path and $quarantine
}

Sigma Rule

title: CVE-2024-7238 VIPRE Symlink Privilege Escalation
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects symbolic link creation in VIPRE directories
author: Valters IT
logsource:
    product: windows
    service: security
    definition: 'Requires Event ID 4663 with access mask for symlink creation'
detection:
    selection:
        EventID: 4663
        ObjectName|contains: 'VIPRE'
        AccessMask: '0x1'  # DELETE
    condition: selection
falsepositives:
    - Legitimate VIPRE operations
level: high

Suricata Rule

alert tcp any any -> any any (msg:"CVE-2024-7238 VIPRE Symlink Exploit Attempt"; flow:to_server; content:"mklink"; nocase; content:"VIPRE"; nocase; content:"Quarantine"; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

• Immediate: Disable the VIPRE Anti Malware Service if not critical, or restrict its ability to delete files via symlink.
• Vendor Patch: Await an official patch from VIPRE. Contact VIPRE support for updates.
• Workaround: Use Windows Defender or another AV solution until a patch is available.
• Monitoring: Enable advanced auditing for symlink creation and file deletion events.
• Least Privilege: Ensure users have minimal privileges to reduce the attack surface.

Valters IT
DevSecOps & Cyber Threat Intelligence