CVE-2021-36385 in Mobile Care
Summary
by MITRE • 08/24/2021
A SQL Injection vulnerability in Cerner Mobile Care 5.0.0 allows remote unauthenticated attackers to execute arbitrary SQL commands via a Fullwidth Apostrophe (aka U+FF07) in the default.aspx User ID field. Arbitrary system commands can be executed through the use of xp_cmdshell.
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Analysis
by VulDB Data Team • 08/26/2021
The vulnerability CVE-2021-36385 represents a critical SQL injection flaw in Cerner Mobile Care version 5.0.0 that exposes the system to remote exploitation by unauthenticated attackers. This vulnerability specifically targets the default.aspx User ID field where input validation is insufficient to prevent malicious SQL payload injection. The attack vector leverages the Fullwidth Apostrophe character U+FF07 which is encoded as a single quote in standard ASCII but appears as a distinct Unicode character in web applications. This particular encoding bypasses many standard input sanitization mechanisms that typically filter out conventional single quote characters used in SQL injection attacks.
The technical exploitation of this vulnerability occurs through the manipulation of the User ID parameter in the default.aspx page where the application fails to properly sanitize user input before incorporating it into SQL database queries. When an attacker submits a malicious payload containing the Fullwidth Apostrophe character, the application processes this input without adequate validation, allowing the attacker to inject arbitrary SQL commands directly into the database execution context. The vulnerability is particularly dangerous because it enables attackers to execute system-level commands through the use of the xp_cmdshell stored procedure, which is a Microsoft SQL Server feature that allows execution of operating system commands from within the database environment. This capability transforms a simple database injection into a full system compromise.
The operational impact of this vulnerability extends far beyond simple data theft or modification. An attacker who successfully exploits this vulnerability gains the ability to execute arbitrary commands on the underlying database server, potentially leading to complete system compromise. The implications include unauthorized data access, data modification or deletion, privilege escalation, and potential lateral movement within the network infrastructure. The fact that this vulnerability is accessible to unauthenticated attackers means that any individual with access to the application interface can potentially exploit it, making it particularly dangerous in environments where the application is publicly accessible or exposed to untrusted networks. This vulnerability also represents a significant risk to patient data integrity in healthcare environments where Cerner Mobile Care systems are commonly deployed, potentially exposing sensitive medical information to unauthorized parties.
Mitigation strategies for CVE-2021-36385 must address both immediate remediation and long-term security architecture improvements. The primary solution involves implementing proper input validation and parameterized queries to prevent SQL injection attacks, ensuring that all user inputs are properly sanitized and escaped before being processed by database systems. Organizations should also disable unnecessary database features such as xp_cmdshell that can be exploited for command execution, and implement comprehensive web application firewalls to detect and block malicious payloads. The vulnerability aligns with CWE-89 which specifically addresses SQL injection flaws, and represents a clear violation of the principle of least privilege as defined in cybersecurity frameworks. From an ATT&CK perspective, this vulnerability maps to T1190 - Exploit Public-Facing Application and T1059 - Command and Scripting Interpreter, indicating that attackers can leverage this flaw to establish persistent access and execute commands on compromised systems. Regular security assessments and input validation testing should be implemented to prevent similar vulnerabilities from emerging in other components of the healthcare information system.