CVE-2025-3092: User Enumeration Information Disclosure

CVE-2025-3092 Overview

CVE-2025-3092 is a username enumeration vulnerability that allows an unauthenticated remote attacker to retrieve valid user names from an unprotected endpoint. The flaw is classified under [CWE-204] (Observable Response Discrepancy) and was disclosed through CERT VDE advisories covering affected industrial and automation products. Because the endpoint requires no authentication, attackers can collect a list of valid accounts from across the network. This information feeds directly into credential-stuffing, password-spraying, and targeted phishing campaigns.

Critical Impact

Unauthenticated network attackers can harvest valid user names without any prior credentials, enabling follow-on credential attacks against high-value accounts.

Affected Products

• Products covered by CERT VDE advisory VDE-2025-035
• Products covered by CERT VDE advisory VDE-2025-038
• Refer to vendor advisories for the complete list of affected versions

Discovery Timeline

• 2025-06-24 - CVE-2025-3092 published to the National Vulnerability Database (NVD)
• 2026-04-15 - Last updated in the NVD database

Technical Details for CVE-2025-3092

Vulnerability Analysis

The vulnerability resides in an unauthenticated HTTP endpoint that responds differently depending on whether a submitted user name exists. An attacker iterates through candidate user names and observes the response to determine which accounts are valid. No credentials, tokens, or prior access are required. The flaw maps to [CWE-204] Observable Response Discrepancy, where the application leaks state information through differences in responses, timing, or error messages.

While username enumeration does not directly compromise data, it reduces the attacker's search space for subsequent authentication attacks. Valid user lists derived from this issue can be combined with leaked password corpora to mount efficient credential-stuffing or password-spraying attacks against the same product or related identity services.

Root Cause

The affected endpoint distinguishes between existing and non-existing accounts in its responses. This may take the form of differing HTTP status codes, response bodies, error messages, or response times. The endpoint also lacks authentication or rate limiting, so attackers can probe it freely from any network position with reachability to the device.

Attack Vector

The attack is performed remotely over the network with low complexity and no user interaction. An attacker sends crafted requests to the unprotected endpoint with candidate user names sourced from common lists, organization directories, or open-source intelligence. By comparing responses, the attacker builds an authoritative roster of valid accounts and then pivots to authentication attacks against the same system or federated services.

No verified public proof-of-concept code is currently available. See the CERT VDE Advisory VDE-2025-035 and CERT VDE Advisory VDE-2025-038 for vendor-specific technical details.

Detection Methods for CVE-2025-3092

Indicators of Compromise

• High volumes of requests to authentication or user-lookup endpoints originating from a single source or small set of IP addresses.
• Sequential or dictionary-style user name parameters in HTTP request logs.
• Repeated requests producing alternating success and failure responses against account-related endpoints.

Detection Strategies

• Inspect web and application logs for enumeration patterns, including consistent request intervals and incremental user name values.
• Establish baseline request rates per source IP for unauthenticated endpoints and alert on statistical anomalies.
• Correlate enumeration attempts with subsequent authentication failures from the same or related sources to identify credential-spraying follow-up activity.

Monitoring Recommendations

• Forward web server, reverse proxy, and application logs to a centralized analytics platform for retention and correlation.
• Track the ratio of successful versus failed lookups on user-facing endpoints to surface probing behavior.
• Monitor authentication telemetry for spikes in failed logins targeting accounts that were recently queried at the unprotected endpoint.

How to Mitigate CVE-2025-3092

Immediate Actions Required

• Apply vendor-supplied patches referenced in CERT VDE Advisory VDE-2025-035 and CERT VDE Advisory VDE-2025-038 as soon as they are available.
• Restrict network access to affected management endpoints to trusted administrative networks only.
• Audit existing accounts and enforce strong, unique passwords plus multi-factor authentication on all user accounts reachable from the affected product.

Patch Information

Consult the linked CERT VDE advisories for vendor-specific fixed versions, affected product identifiers, and update procedures. The advisories are the authoritative source for remediation guidance for this CVE.

Workarounds

• Place affected devices behind a VPN or jump host so that the vulnerable endpoint is not reachable from untrusted networks.
• Apply network access control lists or firewall rules that limit access to authentication endpoints to known administrative source addresses.
• Enable rate limiting and account lockout policies at an upstream proxy to throttle enumeration and downstream credential attacks.