CVE-2021-33420 in replicator
Summary
by MITRE • 12/15/2022
A deserialization issue discovered in inikulin replicator before 1.0.4 allows remote attackers to run arbitrary code via the fromSerializable function in TypedArray object.
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Analysis
by VulDB Data Team • 04/22/2025
The vulnerability identified as CVE-2021-33420 represents a critical deserialization flaw within the inikulin replicator library version 1.0.3 and earlier. This issue stems from improper handling of serialized data structures, specifically affecting the TypedArray object's fromSerializable function. The vulnerability classifies under CWE-502 which encompasses deserialization of untrusted data, making it a significant concern for applications that rely on object serialization for data exchange or storage operations. The flaw exists in the library's deserialization logic where it fails to properly validate or sanitize incoming serialized data before processing it.
Attackers can exploit this vulnerability by crafting malicious serialized data that, when processed through the vulnerable fromSerializable function, triggers arbitrary code execution on the target system. The attack vector is remote, meaning an attacker does not need physical access to the system but can leverage network-based attacks to deliver malicious payloads. The vulnerability's impact is particularly severe because it allows for complete system compromise, potentially enabling attackers to gain full control over affected systems, execute commands with system privileges, and establish persistent access. This type of vulnerability falls under the ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1566.001 for Phishing, as attackers can use the arbitrary code execution to establish further footholds or escalate privileges.
The operational impact of this vulnerability extends beyond immediate code execution, as it can lead to data breaches, system compromise, and potential lateral movement within network environments. Organizations using vulnerable versions of the inikulin replicator library are at risk of having their systems exploited for malicious purposes including data exfiltration, establishing backdoors, or using compromised systems for further attacks. The vulnerability affects any application or service that utilizes the affected library for processing serialized data, particularly those handling user-provided or external data streams. Security teams must consider this vulnerability in their threat modeling exercises and assess their attack surface for potential exploitation.
Mitigation strategies for CVE-2021-33420 include immediate upgrading to version 1.0.4 or later of the inikulin replicator library where the deserialization issue has been addressed. Organizations should also implement input validation and sanitization measures for any serialized data processing, employ secure coding practices that avoid unsafe deserialization patterns, and consider using alternative serialization formats that are less prone to such vulnerabilities. Network segmentation and monitoring for suspicious deserialization activities can provide additional layers of protection. Regular security assessments and dependency updates should be part of the organization's security posture to prevent similar vulnerabilities from being exploited. The fix implemented in version 1.0.4 likely includes proper validation of serialized data structures and enhanced sanitization of input parameters to prevent malicious code injection during deserialization operations.