CVE-2017-16664 in Open Ticket Request System
Summary
by MITRE
Code injection exists in Kernel/System/Spelling.pm in Open Ticket Request System (OTRS) 5 before 5.0.24, 4 before 4.0.26, and 3.3 before 3.3.20. In the agent interface, an authenticated remote attackeer can execute shell commands as the webserver user via URL manipulation.
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Analysis
by VulDB Data Team • 01/11/2023
The vulnerability CVE-2017-16664 represents a critical code injection flaw in the Open Ticket Request System OTRS platform, affecting multiple major versions including 5.0.x before 5.0.24, 4.0.x before 4.0.26, and 3.3.x before 3.3.20. This vulnerability resides within the Kernel/System/Spelling.pm module, which handles spelling correction functionality in the agent interface. The flaw enables authenticated remote attackers to execute arbitrary shell commands with the privileges of the web server user, creating a severe escalation path for potential attackers who can already access the system through legitimate authentication mechanisms.
The technical implementation of this vulnerability stems from improper input validation and sanitization within the spelling correction component. When users interact with the agent interface and utilize spelling correction features, the system processes user-provided input without adequate sanitization, allowing malicious payloads to be injected into system commands. This code injection occurs through URL manipulation techniques where attackers can craft specific parameters that get directly passed to underlying shell commands. The vulnerability aligns with CWE-94, which describes "Improper Control of Generation of Code ('Code Injection')" and specifically relates to CWE-77, "Improper Neutralization of Special Elements used in a Command ('Command Injection')", demonstrating how inadequate input validation creates pathways for arbitrary command execution.
From an operational perspective, this vulnerability presents a significant risk to organizations relying on OTRS for ticket management and customer service operations. The authenticated nature of the exploit means that attackers must first obtain valid credentials, but this is often achievable through various social engineering techniques, credential reuse attacks, or compromised accounts. Once exploited, the vulnerability allows attackers to execute commands with the web server user privileges, potentially leading to complete system compromise, data exfiltration, or lateral movement within the network. The impact extends beyond immediate command execution as attackers can leverage this foothold to escalate privileges, establish persistent access, or deploy additional malware. This vulnerability directly maps to ATT&CK technique T1059.001 for command and scripting interpreter and T1078.004 for valid accounts, demonstrating how legitimate access can be abused for malicious purposes.
Organizations should implement immediate mitigations including applying the vendor-provided patches for versions 5.0.24, 4.0.26, and 3.3.20 respectively, which address the input validation issues in the spelling correction module. Network segmentation and access controls should be enforced to limit exposure of the agent interface to trusted networks only. Additional defensive measures include implementing web application firewalls to detect and block suspicious URL patterns, conducting regular security audits of input validation mechanisms, and monitoring for unusual command execution patterns. System administrators should also consider implementing least privilege principles for web server accounts, ensuring that the web server user has minimal required permissions to reduce the potential impact of successful exploitation. Regular security training for administrators and users helps prevent credential compromise that could lead to exploitation of this vulnerability.