CVE-2025-25236

Executive Summary

CVE-2025-25236 is an observable response discrepancy vulnerability in Omnissa Workspace ONE Unified Endpoint Management (UEM). This flaw allows an unauthenticated, remote attacker to enumerate sensitive information, specifically tenant IDs and user accounts, by analyzing differences in server responses. While the CVSS score is 5.3 (Medium), the information disclosure enables targeted brute-force, password-spraying, and credential-stuffing attacks, significantly increasing the risk of account compromise. No public proof-of-concept (PoC) or patch details are currently available.

Supply Chain & Package Security

This vulnerability is not related to a software package (NPM, PyPI, Go, Ruby). It affects a proprietary enterprise endpoint management platform.

CVSS Breakdown & Threat Level

• CVSS Score: 5.3 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
• Attack Vector: Network (AV:N) – Exploitable remotely.
• Attack Complexity: Low (AC:L) – No special conditions required.
• Privileges Required: None (PR:N) – No authentication needed.
• User Interaction: None (UI:N) – No user action required.
• Scope: Unchanged (S:U) – Impact confined to the vulnerable component.
• Confidentiality: Low (C:L) – Limited information disclosure (tenant IDs, usernames).
• Integrity: None (I:N) – No data modification.
• Availability: None (A:N) – No denial of service.

Threat Level: Elevated. While the direct impact is low, the information leakage enables more severe attacks (credential stuffing, brute-force) that can lead to full account takeover.

Deep Dive & Mechanics

The vulnerability stems from an observable response discrepancy in the Omnissa Workspace ONE UEM authentication or user enumeration endpoints. When an attacker sends requests with different valid and invalid tenant IDs or usernames, the server returns distinct responses (e.g., different HTTP status codes, response body lengths, error messages, or timing). This allows an attacker to systematically enumerate valid identifiers.

Technical Mechanism:

1. The attacker sends a request to a UEM endpoint (e.g., /API/.../login or /API/.../tenant).
2. The server processes the request and returns a response that differs based on whether the provided tenant ID or username exists.
3. The attacker observes these differences (e.g., 200 OK vs. 404 Not Found, or {"error":"Invalid tenant"} vs. {"error":"Invalid credentials"}).
4. By iterating through a list of potential identifiers, the attacker builds a database of valid tenant IDs and user accounts.

Root Cause: The application fails to implement consistent error handling and response formatting for authentication-related queries. This is a classic CWE-204 (Observable Response Discrepancy) issue.

Vulnerable vs. Patched Code

No specific code snippets are available as the vulnerability is unpatched and no patch details exist. However, the vulnerable pattern is:

Vulnerable (Conceptual):

# Vulnerable endpoint
def check_tenant(tenant_id):
    if tenant_exists(tenant_id):
        return {"status": "tenant_found"}
    else:
        return {"error": "invalid_tenant"}

Patched (Conceptual):

# Patched endpoint
def check_tenant(tenant_id):
    # Always return the same response regardless of tenant existence
    return {"status": "processing"}

The fix involves returning identical responses for both valid and invalid identifiers, or using a generic error message that does not reveal the existence of the identifier.

Exploitation & Lab Setup

Red Team (Attacker)

Objective: Enumerate valid tenant IDs and user accounts.

Prerequisites:

• Network access to the Workspace ONE UEM instance.
• A list of potential tenant IDs or usernames (e.g., from OSINT or common patterns).

Exploitation Steps:

1. Identify the vulnerable endpoint: Use a web proxy (e.g., Burp Suite) to intercept login or tenant lookup requests.
2. Craft requests: Send requests with different tenant IDs/usernames.
3. Analyze responses: Look for differences in HTTP status codes, response body, headers, or timing.
4. Automate enumeration: Use a script to iterate through a wordlist and log valid identifiers.

Example Script (Python):

import requests

target = "https://uem.example.com"
wordlist = ["tenant1", "tenant2", "admin", "user123"]

for identifier in wordlist:
    response = requests.post(f"{target}/API/login", json={"tenant": identifier, "username": "test", "password": "test"})
    if "invalid_tenant" not in response.text:
        print(f"Valid tenant: {identifier}")

Blue Team (Defender)

Detection:

• Monitor for repeated requests to authentication endpoints with varying tenant IDs or usernames.
• Look for patterns of sequential or dictionary-based enumeration attempts.
• Alert on unusual response size or status code patterns.

Mitigation:

• Implement rate limiting on authentication endpoints.
• Use generic error messages for all failed authentication attempts.
• Deploy Web Application Firewall (WAF) rules to block enumeration patterns.
• Enable logging and alerting for anomalous authentication behavior.

Indicators of Compromise (IOCs)

• Network IOCs:

  • Repeated HTTP requests to /API/login, /API/tenant, or similar endpoints with varying parameters.
  • Unusual HTTP response size or status code patterns (e.g., 200 vs 404 for different inputs).
  • High volume of requests from a single IP address to authentication endpoints.

• Log IOCs:

  • Log entries showing multiple failed authentication attempts with different tenant IDs or usernames.
  • Log entries with error messages that differ based on input (e.g., "Invalid tenant" vs "Invalid credentials").

• File IOCs:

  • No specific file-based IOCs identified.

Detection Engineering

YARA Rule

rule CVE_2025_25236_Enumeration {
    meta:
        description = "Detects potential enumeration attempts against Omnissa Workspace ONE UEM"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2025-25236"
    strings:
        $s1 = "invalid_tenant" ascii wide nocase
        $s2 = "tenant_found" ascii wide nocase
        $s3 = "invalid_credentials" ascii wide nocase
        $s4 = "user_not_found" ascii wide nocase
    condition:
        any of ($s*) and #s1 > 10
}

Sigma Rule

title: CVE-2025-25236 - Workspace ONE UEM Enumeration Attempts
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects multiple requests to UEM authentication endpoints with varying tenant IDs or usernames
author: Valters IT
date: 2025-04-10
logsource:
    category: web
    product: omnissa_workspace_one_uem
detection:
    selection:
        cs-uri-query|contains:
            - '/API/login'
            - '/API/tenant'
            - '/API/user'
    condition: selection | count() by src_ip > 10 within 5 minutes
falsepositives:
    - Legitimate user enumeration by administrators
level: medium

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"CVE-2025-25236 - Workspace ONE UEM Enumeration Attempt";
    flow:to_server;
    content:"/API/login"; http_uri;
    content:"tenant"; http_client_body;
    threshold: type both, track by_src, count 10, seconds 300;
    classtype:attempted-recon;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Apply vendor patch: Monitor Omnissa for security updates and apply immediately when available.
2. Implement generic error messages: Modify authentication endpoints to return identical responses for valid and invalid identifiers.
3. Rate limiting: Enforce strict rate limiting on authentication and user enumeration endpoints.
4. WAF rules: Deploy Web Application Firewall rules to block enumeration patterns (e.g., multiple requests with varying parameters).

Long-term Measures:

1. Security hardening: Follow Omnissa's security best practices for Workspace ONE UEM deployment.
2. Logging and monitoring: Enable detailed logging and set up alerts for anomalous authentication behavior.
3. Regular security assessments: Conduct penetration testing and vulnerability scanning.
4. User awareness: Educate users about phishing and credential-stuffing risks.

Workarounds (if patch unavailable):

• Restrict network access to the UEM console to trusted IPs only.
• Implement multi-factor authentication (MFA) to mitigate credential-based attacks.
• Use a reverse proxy to add additional security controls.

Valters IT