CVE-2019-1306 in Team Foundation Server
Summary
by MITRE
A remote code execution vulnerability exists when Azure DevOps Server (ADO) and Team Foundation Server (TFS) fail to validate input properly, aka 'Azure DevOps and Team Foundation Server Remote Code Execution Vulnerability'.
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Analysis
by VulDB Data Team • 08/19/2020
This vulnerability affects Microsoft Azure DevOps Server and Team Foundation Server versions prior to 2019 update 1. The flaw resides in the improper validation of user-supplied input within the web application's handling of certain API endpoints. Attackers can exploit this weakness by crafting malicious payloads that bypass input sanitization mechanisms and execute arbitrary code on the affected server. The vulnerability stems from insufficient validation of file upload operations and parameter handling within the application's web interface, creating a path for remote attackers to inject and execute malicious code without authentication. This represents a critical security gap that allows adversaries to gain full control over the affected systems. The vulnerability is classified as a remote code execution flaw that aligns with CWE-20, which describes improper input validation. The attack vector leverages the application's trust in user input without adequate sanitization, enabling attackers to manipulate the application's behavior through crafted requests.
The technical exploitation of this vulnerability occurs when legitimate users interact with the web-based administration interfaces or API endpoints that process file uploads or configuration parameters. Attackers can leverage this weakness by sending specially crafted HTTP requests containing malicious payloads that the application fails to properly validate. The vulnerability allows for arbitrary code execution in the context of the application pool account, which typically runs with elevated privileges on the server. This means successful exploitation can result in complete system compromise, data exfiltration, and potential lateral movement within the network. The flaw is particularly dangerous because it does not require authentication to exploit, making it accessible to any remote attacker who can reach the vulnerable endpoints. The vulnerability affects the authentication and authorization mechanisms by allowing attackers to bypass normal access controls through code injection techniques.
The operational impact of this vulnerability extends beyond immediate system compromise to include significant business continuity risks and data security implications. Organizations using affected versions of Azure DevOps Server and Team Foundation Server face potential exposure to unauthorized access, data breaches, and system downtime. The vulnerability can enable attackers to establish persistent backdoors, modify source code repositories, access sensitive configuration data, and potentially use the compromised systems as launch points for attacks on other network resources. Security teams must consider the implications of this vulnerability on their overall security posture, as it represents a critical weakness in development infrastructure that could be leveraged to compromise entire software development lifecycles. The attack could result in supply chain compromises if attackers modify source code repositories or inject malicious code into development processes.
Mitigation strategies for this vulnerability include applying the official Microsoft security patches released in Azure DevOps Server 2019 update 1 and subsequent versions. Organizations should immediately upgrade their installations to the latest supported versions to eliminate the risk of exploitation. Network segmentation and firewall rules can provide additional protection by restricting access to vulnerable endpoints, though this should not be considered a substitute for proper patching. Implementing web application firewalls and monitoring for suspicious API calls can help detect exploitation attempts. Security teams should also conduct comprehensive vulnerability assessments to identify any potential exploitation attempts and ensure proper monitoring of system logs for unusual activity patterns. The vulnerability demonstrates the importance of proper input validation and secure coding practices as outlined in the ATT&CK framework's command and control techniques, where adversaries establish persistence and maintain access through code execution capabilities. Regular security testing and vulnerability management programs are essential to prevent similar issues from arising in other applications and systems within the organization's infrastructure.