CVE-2020-5577 in Movable Type
Summary
by MITRE
Movable Type series (Movable Type 7 r.4606 (7.2.1) and earlier (Movable Type 7), Movable Type Advanced 7 r.4606 (7.2.1) and earlier (Movable Type Advanced 7), Movable Type for AWS 7 r.4606 (7.2.1) and earlier (Movable Type for AWS 7), Movable Type 6.5.3 and earlier (Movable Type 6.5), Movable Type Advanced 6.5.3 and earlier (Movable Type Advanced 6.5), Movable Type 6.3.11 and earlier (Movable Type 6.3), Movable Type Advanced 6.3.11 and earlier (Movable Type 6.3), Movable Type Premium 1.29 and earlier, and Movable Type Premium Advanced 1.29 and earlier) allow remote authenticated attackers to upload arbitrary files and execute a php script via unspecified vectors.
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Analysis
by VulDB Data Team • 05/14/2020
The vulnerability identified as CVE-2020-5577 represents a critical file upload flaw affecting multiple versions of Movable Type content management systems including both standard and advanced editions across various release series. This vulnerability specifically targets the file upload functionality within these web applications, creating a pathway for authenticated attackers to bypass security controls and execute arbitrary PHP code on the affected servers. The flaw exists in the validation mechanisms that govern file uploads, allowing malicious actors to circumvent intended restrictions and deploy malicious payloads. The vulnerability impacts not only the core Movable Type platforms but also specialized variants such as Movable Type for AWS, which extends the attack surface to cloud-based implementations. Security researchers have classified this issue as a remote code execution vulnerability, as it enables attackers to gain unauthorized access to the underlying server infrastructure and potentially escalate privileges within the system.
The technical implementation of this vulnerability stems from insufficient input validation and inadequate file type checking within the upload handlers of the affected Movable Type versions. Attackers with valid user credentials can exploit this weakness by uploading specially crafted PHP files through the web interface, which then get executed on the server with the privileges of the web application. This particular flaw aligns with CWE-434, which describes "Unrestricted Upload of File with Dangerous Type" and represents a common pattern in web application security where file upload controls fail to properly validate file contents and extensions. The vulnerability enables attackers to bypass standard security measures that typically restrict file uploads to specific, safe formats such as images or documents, instead allowing the upload of executable scripts. The attack vector involves leveraging legitimate authentication mechanisms to access the file upload functionality, making it particularly dangerous as it can be executed by users who already have authorized access to the system.
The operational impact of CVE-2020-5577 extends far beyond simple unauthorized file uploads, as it creates a persistent threat vector that can be exploited for various malicious activities. Once an attacker successfully uploads and executes PHP code, they can establish persistent backdoors, exfiltrate sensitive data, modify website content, or use the compromised system as a launching point for further attacks within the network. The vulnerability is particularly concerning because it affects multiple product lines and versions, meaning organizations running any of these affected Movable Type platforms are at risk. The attack can lead to complete system compromise, data breaches, and unauthorized access to sensitive information stored within the content management system. Additionally, the vulnerability can be exploited for privilege escalation attacks, where attackers leverage the execution capabilities to gain higher-level access to the server infrastructure and potentially compromise other systems within the organization's network. This makes the vulnerability particularly dangerous in enterprise environments where Movable Type systems may be connected to critical business applications and databases.
Organizations affected by CVE-2020-5577 should immediately implement comprehensive mitigation strategies to protect their systems from exploitation. The primary recommendation involves upgrading to patched versions of Movable Type software, as vendors have released updates that address the file upload validation issues. System administrators should also implement additional security controls such as restricting file upload functionality to only trusted users, implementing strict file type validation, and configuring web servers to prevent execution of uploaded files in web-accessible directories. Network segmentation and monitoring solutions should be deployed to detect anomalous file upload activities and potential exploitation attempts. Organizations should conduct thorough security assessments to identify any potential compromise of their systems and review access controls to ensure that only authorized personnel have upload privileges. The vulnerability also highlights the importance of following secure coding practices and implementing proper input validation as outlined in the OWASP Top Ten security guidelines, particularly focusing on preventing unsafe file upload scenarios. Furthermore, organizations should consider implementing web application firewalls and intrusion detection systems to provide additional layers of protection against exploitation attempts. Regular security audits and vulnerability assessments should be conducted to ensure that similar issues are not present in other applications within the organization's infrastructure, as this vulnerability demonstrates the critical importance of maintaining up-to-date security measures across all web applications.