CVE-2025-0589: Octopus Server Information Disclosure Flaw

CVE-2025-0589 Overview

CVE-2025-0589 is an information disclosure vulnerability affecting Octopus Deploy Server when configured to use Active Directory for authentication. The vulnerability allows unauthenticated users to make API requests against two specific endpoints, which return sensitive information from the associated Active Directory environment without proper authorization checks.

When exploited, attackers can retrieve user profile information including email addresses, User Principal Names (UPNs), and display names from one endpoint, as well as group information including Group IDs and display names from the other endpoint. Importantly, this vulnerability does not expose data within the Octopus Server product itself, but rather leaks information from the connected Active Directory infrastructure.

Critical Impact

Unauthenticated attackers can enumerate Active Directory user and group information, potentially enabling reconnaissance for targeted attacks against the organization's identity infrastructure.

Affected Products

• Octopus Deploy Server (affected versions with Active Directory authentication enabled)
• Deployments on Linux kernel-based systems
• Deployments on Microsoft Windows systems

Discovery Timeline

• February 11, 2025 - CVE CVE-2025-0589 published to NVD
• July 2, 2025 - Last updated in NVD database

Technical Details for CVE-2025-0589

Vulnerability Analysis

This vulnerability is classified under CWE-648 (Incorrect Use of Privileged APIs). The flaw exists in the way Octopus Deploy Server handles API requests related to Active Directory integration. Two specific endpoints fail to properly enforce authentication requirements, allowing any network-accessible attacker to query the Active Directory backend for user and group enumeration.

The vulnerability enables information gathering that could facilitate subsequent attacks such as password spraying, social engineering, or targeted phishing campaigns. While the exposed data is limited to display names, email addresses, UPNs, and group information, this reconnaissance data is valuable for attackers planning further intrusion activities.

The network-accessible nature of this vulnerability means that any attacker who can reach the Octopus Deploy Server API can exploit it without requiring any prior authentication or special privileges.

Root Cause

The root cause lies in the improper implementation of authentication controls on two API endpoints that interface with Active Directory. These endpoints were designed to retrieve user and group information for legitimate authentication and authorization workflows but failed to validate that incoming requests originated from authenticated sessions.

This misconfiguration in access control allows the privileged Active Directory query functionality to be invoked by unauthenticated external parties, violating the principle of least privilege.

Attack Vector

The attack is conducted over the network by crafting specific API requests to the vulnerable endpoints. An attacker with network access to the Octopus Deploy Server can:

1. Identify the vulnerable API endpoints used for Active Directory integration
2. Craft HTTP requests targeting these endpoints without providing authentication credentials
3. Parse the responses to extract user profile information (email, UPN, display name)
4. Query the second endpoint to enumerate group information (Group ID, display name)

The attack requires no user interaction and can be automated to rapidly enumerate the entire Active Directory user and group database accessible to the Octopus Deploy Server service account.

Detection Methods for CVE-2025-0589

Indicators of Compromise

• Unusual volume of unauthenticated API requests to Active Directory-related endpoints
• API access logs showing requests to user/group enumeration endpoints without valid session tokens
• Multiple sequential requests from the same source IP targeting AD integration endpoints
• Unexpected external IP addresses querying internal Active Directory data

Detection Strategies

• Monitor Octopus Deploy Server access logs for unauthenticated requests to AD-related API paths
• Implement web application firewall rules to detect and alert on bulk enumeration patterns
• Review API gateway logs for requests targeting user and group lookup endpoints without authentication headers
• Deploy network intrusion detection signatures for known exploitation patterns

Monitoring Recommendations

• Enable verbose logging on Octopus Deploy Server API endpoints
• Configure SIEM alerts for authentication bypass patterns against AD integration components
• Monitor Active Directory logs for unusual query volumes from the Octopus Server service account
• Establish baselines for normal API request volumes and alert on anomalies

How to Mitigate CVE-2025-0589

Immediate Actions Required

• Apply the latest security patches from Octopus Deploy as referenced in Octopus Security Advisory SA2025-01
• Review API access logs for evidence of prior exploitation
• Restrict network access to the Octopus Deploy Server to trusted networks only
• Consider temporary disabling of Active Directory authentication if immediate patching is not possible

Patch Information

Octopus Deploy has released security updates to address this vulnerability. Administrators should consult the Octopus Security Advisory SA2025-01 for specific version information and patch download links. The patch implements proper authentication checks on the affected API endpoints to prevent unauthenticated access to Active Directory query functionality.

Workarounds

• Implement network-level access controls to restrict API access to authenticated internal networks only
• Deploy a reverse proxy or web application firewall to filter requests to vulnerable endpoints
• Temporarily switch to an alternative authentication provider if Active Directory authentication can be disabled
• Use firewall rules to limit access to the Octopus Deploy Server API to known administrator IP ranges