CVE-2019-9057 in CMS Made Simple
Summary
by MITRE
An issue was discovered in CMS Made Simple 2.2.8. In the module FilePicker, it is possible to reach an unserialize call with an untrusted parameter, and achieve authenticated object injection.
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Analysis
by VulDB Data Team • 05/21/2020
The vulnerability identified as CVE-2019-9057 represents a critical security flaw within CMS Made Simple version 2.2.8, specifically within the FilePicker module component. This issue stems from improper input validation and unsafe deserialization practices that allow authenticated attackers to inject malicious objects into the application's execution flow. The vulnerability exists in the context of web content management systems where user input is processed without adequate sanitization, creating a pathway for arbitrary code execution and system compromise. The FilePicker module, designed to facilitate file management operations, inadvertently exposes a dangerous code path that can be exploited by malicious actors who have gained legitimate user credentials.
The technical exploitation of this vulnerability occurs through a serialized object injection attack pattern that leverages the unserialize function with untrusted input parameters. When an authenticated user interacts with the FilePicker module, the application processes user-supplied data through a deserialization mechanism that does not properly validate or sanitize the incoming serialized object. This creates a scenario where an attacker can craft a malicious serialized object that, when processed by the unserialize function, triggers unintended code execution within the application context. The flaw directly aligns with CWE-502, which categorizes unsafe deserialization as a serious vulnerability class that can lead to remote code execution, data manipulation, and privilege escalation. The attack vector requires authentication, making it a authenticated code injection vulnerability that can be particularly dangerous in environments where user privileges are not properly restricted.
The operational impact of CVE-2019-9057 extends beyond simple data corruption or service disruption, as it enables full system compromise when exploited. An authenticated attacker can leverage this vulnerability to execute arbitrary commands on the server hosting the CMS Made Simple installation, potentially leading to complete system takeover. The vulnerability affects not only the integrity of the content management system but also the underlying infrastructure, as successful exploitation can result in persistent backdoor access, data exfiltration, and lateral movement within the network. Organizations using affected versions of CMS Made Simple face significant risk of unauthorized access to sensitive information, modification of web content, and potential use as a launching point for broader attacks against their IT infrastructure. The vulnerability's classification under the ATT&CK framework would place it within the Privilege Escalation and Execution domains, specifically targeting the Deserialization of Untrusted Data technique.
Mitigation strategies for CVE-2019-9057 must address both immediate remediation and long-term security hardening measures. The primary recommendation involves upgrading to a patched version of CMS Made Simple that resolves the unsafe deserialization issue within the FilePicker module. Organizations should also implement strict input validation and sanitization mechanisms to prevent untrusted data from reaching deserialization points. Network segmentation and access controls should be enforced to limit the scope of potential exploitation, while monitoring systems should be configured to detect unusual patterns of file access or modification that might indicate exploitation attempts. Additionally, security teams should conduct regular vulnerability assessments and penetration testing to identify similar unsafe deserialization patterns within other components of their web applications. The implementation of web application firewalls and runtime application self-protection measures can provide additional layers of defense against exploitation attempts. Regular security training for developers and administrators is essential to prevent similar vulnerabilities from being introduced in future code deployments and to ensure proper security practices are maintained throughout the software development lifecycle.