Horizon Alert
Summary of the vulnerability and why it matters
A vulnerability has been identified in older versions of OTRS Community Edition, specifically affecting how it handles user authentication. This could allow an unauthenticated attacker to impersonate existing users and gain unauthorized access to sensitive information or modify data within the system. The main concern is confirming if your environment utilizes these older, vulnerable versions.
- Unauthenticated users can impersonate others.
- Affects older OTRS versions via web access.
- Confirm relevance and exposure in your environment.
Attack Path
How an attacker could exploit the issue
An unauthenticated attacker can impersonate existing users by sending a specially crafted HTTP header. This header tricks the OTRS Community Edition into believing the attacker is already authenticated, bypassing password checks when the system is configured to use HTTP Basic Authentication. The attacker can then access or modify data with the privileges of the impersonated user.
- Unauthenticated remote access required.
- Triggered by a crafted HTTP header.
- Risk of unauthorized data access/modification.
Live Threat
Current exploitation, exposure, and threat context
When OTRS Community Edition 6 or prior is configured with HTTP Basic Authentication, an unauthenticated remote attacker could impersonate existing agent or customer users by sending a crafted `Remote-User` HTTP header. This allows the attacker to access confidential information and modify data or configurations with the privileges of the impersonated user, under conditions where the web server maps attacker-controlled headers to environment variables.
- User and system data.
- Via crafted HTTP request header.
- Unauthorized data access and modification.
Operational Fix
Recommended remediation, mitigation, and detection steps
In real-world deployments, the Application Owner or Platform Team is typically responsible for managing ((OTRS)) Community Edition, as it's a web-based ticketing system. The Security/Network Team will be involved in confirming external reachability and coordinating remediation. The first practical step is to identify all instances of the affected software, confirm their exposure and business criticality, and then engage the accountable owner to plan remediation during a maintenance window.
- Application owners should manage this issue.
- Verify reachability and business impact.
- Plan and coordinate remediation actions.
