CVE-2018-19654 in SCMS
Summary
by MITRE
An issue was discovered in Sales & Company Management System (SCMS) through 2018-06-06. There is a discrepancy in username checking between a component that does string validation, and a component that is supposed to query a MySQL database. Thus, it is possible to register a new account with a duplicate username, as demonstrated by use of the test%c2 string when a test account already exists.
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Analysis
by VulDB Data Team • 04/16/2020
The vulnerability identified as CVE-2018-19654 resides within the Sales & Company Management System version 2018-06-06, presenting a critical authentication flaw that undermines the system's user management integrity. This issue stems from a fundamental inconsistency in the application's username validation mechanism, where different components handle user registration checks in divergent manners. The core problem manifests when the string validation component fails to properly enforce uniqueness constraints that should be maintained by the database query component, creating a window of opportunity for malicious actors to exploit the system's inconsistent validation logic.
The technical implementation of this vulnerability demonstrates a classic case of input validation and database consistency mismatch, specifically categorized under CWE-1072 which addresses inconsistencies in validation and database operations. When attempting to register a new account with a username that already exists in the system, the application's validation logic becomes ineffective due to the discrepancy between the string validation routine and the database query execution. The vulnerability is particularly exploitable through the use of encoded characters such as the test%c2 string pattern, where the percent encoding bypasses the string validation checks while still being processed by the database query component. This inconsistency allows attackers to create duplicate user accounts despite the system's intended duplicate prevention mechanisms.
The operational impact of this vulnerability extends beyond simple account duplication, potentially enabling several serious security implications within the SCMS environment. An attacker could leverage this flaw to create multiple accounts with identical usernames, potentially disrupting normal user operations, causing confusion in user management, and possibly enabling privilege escalation attacks if the system's access controls are not properly enforced across duplicate accounts. The vulnerability also represents a breakdown in the principle of least privilege and proper authentication enforcement, as it allows unauthorized account creation that could lead to further exploitation opportunities. Additionally, this issue could compromise audit trails and user accountability mechanisms within the system, as duplicate entries would create ambiguity in user identification and activity tracking.
Mitigation strategies for CVE-2018-19654 should focus on implementing consistent validation logic across all components involved in user account creation processes. The most effective approach involves synchronizing the string validation routine with database query operations to ensure that all username checks occur consistently before account creation. This includes implementing proper database constraints such as unique indexes on username fields and ensuring that the application layer enforces these constraints through atomic operations that check for existence before attempting to create new records. Organizations should also consider implementing proper input sanitization and validation routines that handle encoded characters appropriately, preventing bypasses through percent encoding or similar techniques. The remediation process should include thorough testing of the username validation logic under various conditions to ensure that the database query component properly enforces uniqueness constraints regardless of how the input is formatted or encoded. This vulnerability aligns with ATT&CK technique T1078 which covers valid accounts and credential access, as the ability to create duplicate accounts can facilitate unauthorized access and privilege escalation within the system.