CVE-2018-16587 in Open Ticket Request System
Summary
by MITRE
In Open Ticket Request System (OTRS) 4.0.x before 4.0.32, 5.0.x before 5.0.30, and 6.0.x before 6.0.11, an attacker could send a malicious email to an OTRS system. If a user with admin permissions opens it, it causes deletions of arbitrary files that the OTRS web server user has write access to.
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Analysis
by VulDB Data Team • 05/19/2023
The vulnerability CVE-2018-16587 represents a critical server-side request forgery flaw in the Open Ticket Request System that affects multiple versions including 4.0.x before 4.0.32, 5.0.x before 5.0.30, and 6.0.x before 6.0.11. This vulnerability falls under the CWE-935 category of Improper Neutralization of Directives in Deserialized Data, specifically manifesting as a deserialization vulnerability that allows for arbitrary file deletion operations. The flaw exists within the email processing functionality of OTRS where the system fails to properly validate and sanitize email content before processing, creating an attack vector through which malicious actors can manipulate the system's file handling mechanisms.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious email and delivers it to a targeted OTRS system. When an administrator with appropriate permissions opens this specially crafted email, the system processes the email content without adequate sanitization, leading to the execution of arbitrary file deletion commands. The vulnerability leverages the fact that the OTRS web server user possesses write permissions to critical system directories, allowing the attacker to target files within these accessible locations. This represents a privilege escalation scenario where a simple email interaction can result in significant system compromise through unauthorized file manipulation.
The operational impact of CVE-2018-16587 extends beyond simple data loss as it provides attackers with the capability to disrupt system operations, delete critical configuration files, remove security-related components, and potentially establish persistent access points within the compromised environment. The vulnerability affects organizations that rely heavily on email-based ticketing systems, as it transforms routine email interactions into potential attack vectors. Given that administrative users typically open emails without additional security scrutiny, the attack surface is significantly expanded, making this vulnerability particularly dangerous in enterprise environments where OTRS is deployed for customer support and internal ticket management.
Organizations should immediately implement security patches addressing the specific deserialization vulnerabilities in OTRS versions mentioned in the advisory, following the principle of least privilege by restricting the web server user's write permissions to only necessary directories. Network segmentation and email filtering mechanisms should be enhanced to detect and quarantine suspicious email content, while regular security audits should verify that the patched versions are properly deployed across all systems. The vulnerability aligns with ATT&CK technique T1190 - Exploit Public-Facing Application, highlighting the need for comprehensive application security controls and regular vulnerability assessments to prevent similar exploitation vectors from compromising organizational security postures.