CVE-2024-7826

Executive Summary

CVE-2024-7826 is a vulnerability in Webroot SecureAnywhere - Web Shield, specifically within the wrURL.Dll module. The issue is classified as an "Improper Check for Unusual or Exceptional Conditions" (CWE-754), which allows for functionality misuse. This vulnerability affects versions before 2.1.2.3 on Windows (ARM, 64-bit, 32-bit). The CVSS score is 0.0, indicating that no official CVSS vector has been assigned, and the EPSS score is 0.0%, suggesting low exploitation likelihood in the wild. No public proof-of-concept (PoC) or exploit code is available. The patch status is unknown, and no official patch details have been released.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a native Windows DLL component of Webroot SecureAnywhere.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (Unassigned)
• CVSS Vector: UNKNOWN
• EPSS Score: 0.0% (Low exploitation probability)
• Threat Level: Low (due to no public exploit, low EPSS, and unassigned CVSS)

The lack of a CVSS vector and public exploit data suggests this vulnerability may be difficult to exploit or requires specific conditions. However, the potential for functionality misuse could lead to security feature bypass or denial of service.

Deep Dive & Mechanics

The vulnerability resides in the wrURL.Dll module of Webroot SecureAnywhere - Web Shield. This module is responsible for URL filtering and web threat protection. The improper check for unusual or exceptional conditions means that the DLL fails to handle certain edge cases or malformed inputs correctly. This could allow an attacker to:

• Bypass URL filtering rules.
• Cause the Web Shield component to crash or behave unexpectedly.
• Potentially disable web protection features.

The exact trigger mechanism is not publicly documented, but it likely involves sending specially crafted network traffic or manipulating the DLL's input parameters.

Vulnerable vs. Patched Code

No specific code diff is available. The vulnerable version is before 2.1.2.3. The patched version (2.1.2.3 or later) presumably includes additional input validation and exception handling in wrURL.Dll to prevent the misuse.

Exploitation & Lab Setup

Red Team

Since no public exploit exists, a red team would need to reverse-engineer the wrURL.Dll module to identify the exact conditions that trigger the vulnerability. Potential steps:

1. Setup: Install Webroot SecureAnywhere version < 2.1.2.3 on a Windows VM.
2. Analysis: Use a debugger (e.g., x64dbg) to attach to the Web Shield process and monitor wrURL.Dll for unusual input handling.
3. Fuzzing: Fuzz the DLL's exported functions or network input to find crash conditions.
4. Exploit Development: Craft a payload that triggers the improper check, potentially leading to a denial of service or bypass.

Example (hypothetical):

# Hypothetical fuzzing script
import socket

def send_malformed_packet():
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.connect(("127.0.0.1", 80))
    # Malformed HTTP request to trigger the vulnerability
    payload = b"GET /" + b"A"*1000 + b" HTTP/1.1\r\nHost: test\r\n\r\n"
    sock.send(payload)
    sock.close()

Blue Team

• Detection: Monitor for crashes or unusual behavior in the wrURL.Dll module. Use process monitoring tools to detect when the Web Shield component terminates unexpectedly.
• Mitigation: Apply the vendor patch (version 2.1.2.3 or later) as soon as it becomes available. If no patch is available, consider disabling the Web Shield component temporarily or using network segmentation to limit exposure.
• Hunting: Search for logs indicating Web Shield failures or crashes, especially those related to URL filtering.

Indicators of Compromise (IOCs)

• File Hash (wrURL.Dll): Unknown (no specific hash provided)
• Process: WRShield.exe or related Webroot processes crashing
• Event Logs: Windows Application Event Log entries with source "Webroot" and event IDs related to crashes
• Network: Unusual HTTP requests that cause the Web Shield to fail

Detection Engineering

YARA Rule

rule CVE_2024_7826_Webroot_wrURL_DLL {
    meta:
        description = "Detects potentially vulnerable wrURL.Dll version for CVE-2024-7826"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-7826"
    strings:
        $dll_name = "wrURL.dll" nocase
        $version_string = "2.1.2." ascii wide
    condition:
        $dll_name and not $version_string
}

Sigma Rule

title: Webroot SecureAnywhere Web Shield Crash
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects potential exploitation of CVE-2024-7826 via Web Shield crashes
author: Valters IT
date: 2025-04-10
logsource:
    product: windows
    service: application
detection:
    selection:
        Provider_Name: 'Webroot'
        EventID: 1000  # Application Error
        Message|contains: 'wrURL.dll'
    condition: selection
falsepositives:
    - Legitimate crashes due to other reasons
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-7826 Webroot Web Shield Potential Exploit"; flow:to_server; content:"GET"; http_method; content:"/"; http_uri; pcre:"/^\/[A-Z]{100,}/"; sid:1000001; rev:1;)

Remediation & Mitigation

1. Patch: Update Webroot SecureAnywhere - Web Shield to version 2.1.2.3 or later as soon as the vendor releases a patch.
2. Workaround: If patching is not possible, consider disabling the Web Shield component temporarily or using alternative web filtering solutions.
3. Monitoring: Enable detailed logging for Webroot processes and monitor for crashes or unusual behavior.
4. Network Controls: Use network segmentation to limit exposure of vulnerable systems to untrusted networks.

Valters IT
DevSecOps & Cyber Threat Intelligence