CVE-2018-7668 in TestLink
Summary
by MITRE
TestLink through 1.9.16 allows remote attackers to read arbitrary attachments via a modified ID field to /lib/attachments/attachmentdownload.php.
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Analysis
by VulDB Data Team • 01/10/2020
The vulnerability identified as CVE-2018-7668 affects TestLink versions 1.9.16 and earlier, presenting a critical security flaw that enables remote attackers to access unauthorized attachments within the system. This issue stems from insufficient input validation and access control mechanisms within the attachment download functionality, specifically in the /lib/attachments/attachmentdownload.php component. The vulnerability operates by manipulating the ID field parameter, which allows attackers to bypass normal access controls and retrieve attachments that should otherwise be restricted to authorized users only.
The technical implementation of this vulnerability resides in the improper validation of user-supplied input within the attachment download script. When a user requests an attachment through the download interface, the system should verify that the requesting user has appropriate permissions to access the specified attachment. However, the flawed implementation fails to properly authenticate and authorize access attempts, creating a path for privilege escalation through parameter manipulation. Attackers can construct malicious requests by modifying the ID field to reference attachments belonging to other users or system resources, effectively circumventing the intended access controls. This represents a classic case of insufficient authorization checks that aligns with CWE-285, which addresses improper authorization in software systems.
The operational impact of this vulnerability extends beyond simple data exposure, as it can lead to comprehensive information disclosure across the TestLink environment. Attackers can potentially access sensitive test documentation, project files, user credentials, or other confidential materials stored as attachments within the system. This unauthorized access capability undermines the fundamental security model of TestLink, which relies on proper access controls to protect project data and maintain confidentiality. The vulnerability affects the integrity and availability of the system's attachment management functionality, potentially leading to data breaches and compliance violations in regulated environments. Organizations using TestLink versions prior to 1.9.17 face significant risk of unauthorized data access and potential system compromise through this pathway.
Mitigation strategies for CVE-2018-7668 require immediate implementation of access control improvements and input validation measures. The most effective solution involves updating to TestLink version 1.9.17 or later, which includes proper authorization checks and input sanitization for the attachment download functionality. System administrators should also implement additional defensive measures including network segmentation to limit access to the attachment download endpoints, implementing robust logging and monitoring for suspicious download attempts, and conducting regular security assessments of the application's access control mechanisms. The vulnerability demonstrates the importance of proper input validation and authorization checking, principles that align with ATT&CK technique T1213.002 for Credential Access and T1078.004 for Valid Accounts, as attackers can leverage compromised or unauthorized access to extract sensitive information through manipulated parameters. Organizations should also consider implementing web application firewalls and access control lists to further protect against similar parameter manipulation attacks.