CVE-2017-7220 in Documentum Content Server
Summary
by MITRE
OpenText Documentum Content Server allows superuser access via sys_obj_save or save of a crafted object, followed by an unauthorized "UPDATE dm_dbo.dm_user_s SET user_privileges=16" command, aka an "RPC save-commands" attack. NOTE: this vulnerability exists because of an incomplete fix for CVE-2015-4532.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 09/19/2020
The vulnerability described in CVE-2017-7220 represents a critical privilege escalation flaw within OpenText Documentum Content Server that enables unauthorized users to gain superuser access through carefully crafted object manipulation and database command execution. This vulnerability specifically targets the RPC save-commands functionality and exploits a weakness in the system's authorization mechanisms that was partially addressed in a previous patch for CVE-2015-4532. The attack vector involves a two-step process where an attacker first crafts a malicious object and saves it using the sys_obj_save or save functions, followed by execution of an unauthorized database update command that modifies user privileges. This flaw fundamentally undermines the content management system's security model by allowing arbitrary users to elevate their privileges from standard user status to superuser level, which provides complete administrative control over the system.
The technical implementation of this vulnerability stems from insufficient input validation and authorization checks within the Documentum Content Server's object persistence layer. When the sys_obj_save or save functions are invoked with crafted parameters, the system fails to properly verify the user's authorization level before executing the underlying database operations. The subsequent database command dm_dbo.dm_user_s SET user_privileges=16 directly modifies the user privilege structure within the Documentum repository, effectively granting the attacker superuser privileges. This represents a classic case of insufficient privilege checking and inadequate access control enforcement that aligns with CWE-284, which addresses inadequate access control mechanisms in software systems. The vulnerability operates at the intersection of application-level object handling and database-level privilege management, creating a path for privilege escalation that bypasses normal authentication and authorization procedures.
The operational impact of CVE-2017-7220 is severe and far-reaching, as it allows attackers to completely compromise the Documentum Content Server environment. Once an attacker successfully executes this attack, they gain full administrative privileges including the ability to create, modify, or delete any content within the repository, access all user accounts, modify system configurations, and potentially exfiltrate sensitive data. The vulnerability affects the entire content management ecosystem, as it enables attackers to manipulate documents, user permissions, and system settings without detection. Organizations using Documentum Content Server are particularly vulnerable because the attack requires minimal prerequisites beyond basic access to the system's RPC interface, making it accessible to attackers who may only have limited initial access. This type of vulnerability directly violates the principle of least privilege and represents a critical failure in the system's security architecture, as it allows for complete system compromise through a single attack vector.
Mitigation strategies for CVE-2017-7220 must address both the immediate vulnerability and the underlying architectural issues that enable the attack. Organizations should implement immediate patches provided by OpenText to address the specific RPC save-commands vulnerability, while also strengthening overall access controls and monitoring mechanisms. The recommended approach includes implementing comprehensive input validation for all object creation and modification operations, enforcing strict authorization checks before executing any database modifications, and deploying network segmentation to limit access to the Documentum RPC interfaces. Additionally, organizations should establish robust audit logging and monitoring of database privilege changes, as well as implement regular security assessments to identify similar authorization bypass vulnerabilities. This vulnerability highlights the importance of proper privilege management and input validation, aligning with ATT&CK technique T1068 which covers local privilege escalation through application flaws, and demonstrates the need for comprehensive security testing that includes both functional and security aspects of enterprise content management systems. The incomplete fix for CVE-2015-4532 suggests that organizations should perform thorough regression testing when applying security patches to ensure that previous vulnerabilities have been properly addressed and that new attack vectors have not been inadvertently created.