CVE-2018-3728 in Hoek Node Module
Summary
by MITRE
hoek node module before 5.0.3 suffers from a Modification of Assumed-Immutable Data (MAID) vulnerability via 'merge' and 'applyToDefaults' functions, which allows a malicious user to modify the prototype of "Object" via __proto__, causing the addition or modification of an existing property that will exist on all objects.
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Analysis
by VulDB Data Team • 02/24/2023
The CVE-2018-3728 vulnerability represents a critical modification of assumed-immutable data flaw within the hoek node module version 5.0.3 and earlier. This vulnerability specifically targets the merge and applyToDefaults functions that are commonly used for object manipulation in node.js applications. The flaw allows attackers to exploit the prototype pollution mechanism by manipulating the _proto_ property, which fundamentally undermines the expected behavior of object-oriented programming constructs in javascript environments. The vulnerability stems from the module's failure to properly sanitize input when merging objects, creating opportunities for malicious actors to inject prototype properties that persist across all object instances within the application's runtime environment.
The technical implementation of this vulnerability exploits the inherent characteristics of javascript's prototype chain mechanism. When the merge function processes objects containing properties with names like _proto_ or constructor, it directly assigns these values to the target object without proper validation or sanitization. This allows attackers to inject malicious prototype properties that get propagated to all objects in the application, effectively creating a persistent backdoor or data manipulation vector. The vulnerability is particularly dangerous because it operates at the foundational level of object creation and inheritance, making it difficult to detect and remediate. According to CWE-471, this represents a specific type of prototype pollution vulnerability where the application's object model becomes corrupted through improper handling of prototype properties.
The operational impact of CVE-2018-3728 extends far beyond simple data corruption, potentially enabling attackers to execute arbitrary code or manipulate application behavior at runtime. When prototype pollution occurs, it can lead to various security consequences including but not limited to remote code execution, privilege escalation, and denial of service conditions. The vulnerability affects numerous applications that depend on the hoek module, particularly those using popular frameworks like hapi.js, which makes the impact widespread across the node.js ecosystem. Attackers can leverage this vulnerability to modify critical application behavior by manipulating prototype properties that affect the execution flow of applications. This aligns with ATT&CK technique T1059.007 for command and scripting interpreter, where prototype pollution can be used to establish persistent access through modified object behavior.
Mitigation strategies for CVE-2018-3728 require immediate action to upgrade the hoek module to version 5.0.3 or later, which includes proper prototype sanitization mechanisms. Organizations should conduct comprehensive vulnerability assessments to identify all applications and dependencies that utilize affected versions of the hoek module, particularly in supply chain components that may indirectly reference vulnerable versions. The remediation process should include not only updating the primary dependency but also scanning for transitive dependencies that might still reference older versions. Security teams must implement runtime monitoring to detect prototype pollution attempts and establish proper input validation procedures for all object merging operations. Additionally, developers should adopt secure coding practices that avoid direct assignment of user-controlled data to prototype properties and implement proper sanitization routines before object merging operations occur.