CVE-2018-8602 in Team Foundation Server
Summary
by MITRE
A Cross-site Scripting (XSS) vulnerability exists when Team Foundation Server does not properly sanitize user provided input, aka "Team Foundation Server Cross-site Scripting Vulnerability." This affects Team.
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Analysis
by VulDB Data Team • 04/12/2020
The CVE-2018-8602 vulnerability represents a critical cross-site scripting flaw within Microsoft Team Foundation Server that fundamentally compromises web application security. This vulnerability arises from insufficient input validation and sanitization mechanisms within the server's processing pipeline, allowing malicious actors to inject malicious scripts into web interfaces that are subsequently executed by unsuspecting users. The vulnerability specifically impacts the Team Foundation Server environment where user-provided data fails to undergo proper sanitization before being rendered in web contexts, creating an exploitable vector for attackers to manipulate the application's behavior and compromise user sessions.
The technical flaw manifests when the Team Foundation Server receives user input through various web interfaces and forms without implementing adequate sanitization measures. This allows attackers to craft malicious payloads containing script code that gets stored and later executed in the context of other users' browsers. The vulnerability stems from a lack of proper output encoding and input validation mechanisms within the server's web rendering components. According to CWE classification, this vulnerability maps to CWE-79 which specifically addresses Cross-site Scripting flaws, where the weakness occurs in the data validation and output encoding phases of web application development. The vulnerability exists in the server's handling of user-supplied data within HTML contexts, failing to properly escape special characters and script tags that could alter the intended behavior of web pages.
The operational impact of this vulnerability extends beyond simple data theft or session hijacking, as it provides attackers with the capability to perform a wide range of malicious activities within the compromised environment. An attacker could leverage this vulnerability to execute arbitrary JavaScript code in the context of authenticated users, potentially leading to full compromise of user accounts, data exfiltration, or the ability to manipulate project data within Team Foundation Server. The vulnerability affects the integrity and confidentiality of the entire Team Foundation Server ecosystem, particularly impacting users who have access to sensitive project information, source code repositories, and development workflows. This vulnerability aligns with ATT&CK technique T1531 which focuses on establishing persistence through web shells and malicious script injection, while also supporting T1213 which covers data exploitation through compromised user sessions.
Mitigation strategies for CVE-2018-8602 should prioritize immediate patch deployment from Microsoft, as the vulnerability requires core server updates to address the underlying sanitization flaws. Organizations should implement comprehensive input validation at multiple layers including client-side and server-side filtering, alongside robust output encoding mechanisms to prevent script injection attempts. Security teams should establish monitoring protocols to detect anomalous user behavior and malformed input patterns that might indicate exploitation attempts. Network segmentation and privileged access controls should be reinforced to limit the potential damage from successful exploitation attempts. The implementation of Content Security Policy headers can provide additional defense-in-depth measures to prevent execution of unauthorized scripts, while regular security assessments of web applications should include thorough testing for XSS vulnerabilities. Organizations must also consider implementing web application firewalls specifically configured to detect and block common XSS attack patterns targeting Team Foundation Server components.