CVE-2019-0647 in Team Foundation Server
Summary
by MITRE
An information disclosure vulnerability exists when Team Foundation Server does not properly handle variables marked as secret, aka "Team Foundation Server Information Disclosure Vulnerability." This affects Team.
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Analysis
by VulDB Data Team • 05/02/2020
The vulnerability identified as CVE-2019-0647 represents a critical information disclosure flaw within Microsoft Team Foundation Server that undermines the security of sensitive data handling processes. This vulnerability specifically targets the server's improper management of variables designated as secret, creating potential exposure pathways for confidential information that should remain protected within the system's secure environment. The flaw manifests when the server fails to adequately restrict access to variables that are explicitly marked with secret attributes, thereby allowing unauthorized disclosure of sensitive configuration data that could include credentials, API keys, or other critical system information.
From a technical perspective, this vulnerability operates at the variable handling and access control level within Team Foundation Server's infrastructure. The system's failure to properly enforce secret variable restrictions creates a condition where information that should be protected through access controls becomes accessible to users who should not have visibility into these confidential elements. This represents a fundamental breakdown in the server's information protection mechanisms, where the distinction between public and private variables becomes blurred due to inadequate implementation of security controls. The flaw exists in how the server processes and manages variable attributes, particularly when these attributes indicate sensitive nature, leading to potential exposure of data that should remain restricted.
The operational impact of this vulnerability extends beyond simple data exposure, potentially enabling attackers to gain access to critical system components and resources. When secret variables containing authentication credentials or system configuration details are disclosed, it can lead to unauthorized access to underlying systems, compromise of development environments, and potential escalation of privileges within the team's operational infrastructure. This vulnerability affects not only the immediate confidentiality of stored information but also undermines the trust model that Team Foundation Server relies upon for secure collaboration and development processes. The exposure of secret variables can result in unauthorized access to source code repositories, build systems, and deployment environments that are integral to software development workflows.
Organizations utilizing Team Foundation Server must implement immediate mitigations to address this vulnerability, including applying available security patches from Microsoft and reviewing current variable management practices within their systems. The recommended approach involves strengthening access controls around secret variables, implementing additional monitoring for unauthorized access attempts, and conducting comprehensive audits of variable usage patterns to identify potential exposure risks. Security teams should also consider implementing network segmentation and enhanced logging mechanisms to detect and prevent exploitation attempts. This vulnerability aligns with CWE-200, which addresses information exposure, and represents a specific instance of inadequate access control mechanisms that could be exploited through techniques classified under the ATT&CK framework's credential access and defense evasion domains. The vulnerability's impact is further compounded by its potential to enable lateral movement within development environments and compromise the integrity of the entire software development lifecycle processes that depend on secure variable handling practices.