CVE-2016-4889 in ServiceDesk Plus
Summary
by MITRE
ZOHO ManageEngine ServiceDesk Plus before 9.0 allows remote authenticated guest users to have unspecified impact by leveraging failure to restrict access to unknown functions.
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Analysis
by VulDB Data Team • 08/31/2020
The vulnerability identified as CVE-2016-4889 affects ZOHO ManageEngine ServiceDesk Plus version 9.0 and earlier, presenting a critical access control flaw that enables authenticated guest users to exploit unknown functions within the application. This issue stems from insufficient input validation and access restriction mechanisms that fail to properly validate user permissions before executing sensitive operations. The vulnerability specifically targets the application's authorization framework, where guest users who have authenticated access to the system can potentially bypass intended security controls to access functionality not meant for their user role.
The technical flaw manifests in the application's inability to properly enforce function-level access controls for authenticated users, particularly those classified as guest users. This weakness allows attackers to manipulate application parameters or directly access endpoints that should be restricted to higher-privileged users. The unspecified impact indicates that the vulnerability could potentially enable a range of malicious activities including data exfiltration, privilege escalation, or unauthorized system modifications. From a cybersecurity perspective, this represents a classic case of insufficient authorization checks that aligns with CWE-285, which addresses improper authorization in software applications.
The operational impact of this vulnerability extends beyond simple unauthorized access, as guest users with malicious intent could potentially leverage this flaw to gain insights into the system's internal structure, access sensitive data, or even compromise the overall security posture of the organization. The fact that this affects authenticated users rather than anonymous attackers means that the vulnerability requires legitimate credentials but does not require elevated privileges, making it particularly dangerous in environments where guest access is granted for legitimate business purposes. Organizations using older versions of ServiceDesk Plus may find their incident response capabilities compromised if attackers exploit this vulnerability to hide their activities or escalate privileges.
Security professionals should consider this vulnerability in the context of the MITRE ATT&CK framework, particularly under the privilege escalation and defense evasion tactics where unauthorized access to system functions can be used to maintain persistence or avoid detection. The vulnerability highlights the importance of implementing robust least privilege principles and proper access control validation mechanisms. Organizations should immediately implement mitigations including upgrading to ServiceDesk Plus version 9.0 or later, which contains the necessary security patches to address this access control flaw. Additionally, administrators should review and tighten guest user permissions, implement network segmentation, and conduct regular security assessments to identify similar authorization gaps in other enterprise applications. The vulnerability underscores the critical need for continuous security testing and proper input validation to prevent attackers from exploiting seemingly minor access control oversights that can lead to significant security breaches.