CVE-2024-7824

Executive Summary

CVE-2024-7824 is a type confusion vulnerability in Webroot SecureAnywhere - Web Shield, specifically within the wrUrl.Dll module. This flaw allows an attacker to misuse the functionality of the software by providing a resource of an incompatible type, leading to unexpected behavior. The vulnerability affects Windows, ARM, 64-bit, and 32-bit platforms. As of this report, no official patch has been released, and no public proof-of-concept (PoC) or exploit code is available. The EPSS score is 0.0%, indicating a low probability of exploitation in the wild currently, but the lack of a patch makes it a latent risk.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a native Windows application vulnerability.

CVSS Breakdown & Threat Level

The CVSS vector is not provided in the NVD data. However, based on the nature of the vulnerability (type confusion leading to functionality misuse), a reasonable estimate would be:

• Attack Vector (AV): Local (L) – requires local access to the system.
• Attack Complexity (AC): Low (L) – type confusion can be triggered with crafted input.
• Privileges Required (PR): Low (L) – attacker needs some user privileges.
• User Interaction (UI): Required (R) – user must perform an action (e.g., browse to a malicious site).
• Scope (S): Unchanged (U) – vulnerability affects the component only.
• Confidentiality (C): Low (L) – potential for information disclosure.
• Integrity (I): Low (L) – potential for data manipulation.
• Availability (A): Low (L) – potential for denial of service.

Estimated CVSS v3.1 Score: 5.0 (Medium)

Threat Level: Medium. The vulnerability is unpatched, but exploitation complexity is moderate and no public exploits exist.

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 issue is a type confusion (CWE-843), where the software accesses a resource using an incompatible type. In the context of wrUrl.Dll, this likely occurs when parsing or processing URL data or web content.

Technical Details:

• The module may allocate memory for a specific data type (e.g., a string or structure) but then interpret that memory as a different type.
• An attacker can craft a malicious web page or URL that, when processed by the Web Shield, causes the type confusion.
• This can lead to:
  • Functionality Misuse: The Web Shield may incorrectly classify or handle the malicious content, allowing it to bypass security checks.
  • Memory Corruption: In some cases, type confusion can lead to buffer overflows or arbitrary code execution, though the NVD description specifically mentions "Functionality Misuse."

Attack Vector:

• The attacker must entice a user running Webroot SecureAnywhere to visit a malicious website or open a crafted file.
• The Web Shield component processes the URL or content, triggering the type confusion.
• The attacker can then bypass web filtering, potentially delivering malware or exfiltrating data.

Vulnerable vs. Patched Code

No patch is currently available. The vulnerable version is wrUrl.Dll before version 2.1.2.3. The patched version (2.1.2.3 or later) is expected to include proper type checking and validation.

Hypothetical Vulnerable Code (C++):

void ProcessUrlData(void* data, DWORD size) {
    // Vulnerable: assumes data is always a URL string
    URL_STRUCT* url = (URL_STRUCT*)data; // Type confusion if data is not URL_STRUCT
    // Process url->host, url->path, etc.
}

Hypothetical Patched Code:

void ProcessUrlData(void* data, DWORD size) {
    // Patched: validate type before casting
    if (size < sizeof(URL_STRUCT)) {
        // Handle error
        return;
    }
    URL_STRUCT* url = (URL_STRUCT*)data;
    // Additional validation of url fields
    if (!IsValidUrl(url)) {
        // Handle error
        return;
    }
    // Process url->host, url->path, etc.
}

Exploitation & Lab Setup

No public exploit code is available. The following is a hypothetical lab setup for testing.

Red Team (Offensive)

Lab Environment:

• Windows 10/11 VM with Webroot SecureAnywhere (vulnerable version < 2.1.2.3) installed.
• Attacker machine (Kali Linux) with a web server hosting a malicious page.

Steps:

1. Set up a malicious web page that sends crafted HTTP responses to trigger the type confusion.
2. Use a tool like Burp Suite to intercept and modify traffic.
3. Host the page and send the link to the victim via phishing email.
4. When the victim visits the page, the Web Shield processes the malicious data, causing the type confusion.
5. Monitor for Web Shield crashes or bypass of URL filtering.

Hypothetical Exploit Code (Python):

import socket

def send_malicious_response(client_socket):
    response = b"HTTP/1.1 200 OK\r\n"
    response += b"Content-Type: text/html\r\n"
    response += b"Content-Length: 100\r\n"
    response += b"\r\n"
    # Crafted data to trigger type confusion in wrUrl.Dll
    response += b"\x41" * 100  # Placeholder for malicious payload
    client_socket.send(response)

# Server setup
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind(('0.0.0.0', 8080))
server.listen(1)
print("Listening on port 8080...")
while True:
    client, addr = server.accept()
    print(f"Connection from {addr}")
    send_malicious_response(client)
    client.close()

Blue Team (Defensive)

Detection:

• Monitor for crashes of wrUrl.Dll or Webroot processes.
• Look for unusual network traffic to known malicious domains.
• Use endpoint detection and response (EDR) tools to detect type confusion exploitation attempts.

Mitigation:

• Apply the patch when available (version 2.1.2.3 or later).
• If no patch, consider disabling the Web Shield component temporarily (not recommended).
• Implement network segmentation and web filtering at the perimeter.
• Educate users about phishing attacks.

Indicators of Compromise (IOCs)

• File Hashes (SHA256): (None available, but monitor for modified wrUrl.Dll)
• Process Names: WRShield.exe, WRUrl.dll
• Network Indicators: Connections to IPs hosting malicious content that triggers the vulnerability.
• Registry Keys: (None specific)
• Log Entries: Event logs showing crashes of WRUrl.dll or Webroot service failures.

Detection Engineering

YARA Rule

rule CVE_2024_7824_TypeConfusion {
    meta:
        description = "Detects potential exploitation of CVE-2024-7824 in wrUrl.Dll"
        author = "Valters IT"
        date = "2025-04-10"
        hash = "unknown"
    strings:
        $s1 = "wrUrl.Dll" nocase
        $s2 = "URL_STRUCT" nocase
        $s3 = "ProcessUrlData" nocase
    condition:
        $s1 and ($s2 or $s3)
}

Sigma Rule

title: CVE-2024-7824 Webroot Web Shield Type Confusion
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects crashes or errors related to wrUrl.Dll type confusion
author: Valters IT
date: 2025/04/10
logsource:
    product: windows
    service: application
detection:
    selection:
        EventID: 1000
        Provider_Name: "Application Error"
        Data: "*wrUrl.Dll*"
    condition: selection
falsepositives:
    - Unknown
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-7824 Webroot Web Shield Type Confusion Attempt"; flow:to_server; content:"|41 41 41 41|"; depth:100; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

1. Patch: Apply the official patch from Webroot when version 2.1.2.3 or later is released.
2. Workaround: If patching is not possible, consider disabling the Web Shield component (not recommended as it reduces security).
3. Monitoring: Implement the detection rules above to identify exploitation attempts.
4. User Training: Educate users on phishing risks and safe browsing habits.
5. Network Controls: Use web filtering and intrusion prevention systems (IPS) to block malicious content.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert