CVE-2020-8031 in Open Build Service
Summary
by MITRE • 02/12/2021
A Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Open Build Service allows remote attackers to store JS code in markdown that is not properly escaped, impacting confidentiality and integrity. This issue affects: Open Build Service versions prior to 2.10.8.
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Analysis
by VulDB Data Team • 02/28/2021
The CVE-2020-8031 vulnerability represents a critical cross-site scripting flaw within the Open Build Service platform that undermines web application security through improper input sanitization during page generation processes. This vulnerability specifically targets the markdown processing functionality where user-supplied content is not adequately escaped or neutralized before being rendered in web pages. The flaw enables remote attackers to inject malicious javascript code through markdown input fields, creating persistent XSS attack vectors that can compromise user sessions and data integrity. The vulnerability affects all versions of Open Build Service prior to 2.10.8, making it a significant concern for organizations relying on older deployments of this open source build management system. The issue stems from inadequate input validation and output encoding mechanisms that fail to properly sanitize user-generated content before it is stored and subsequently rendered in web contexts.
The technical implementation of this vulnerability demonstrates a classic improper neutralization of input during web page generation pattern that aligns with CWE-79, which specifically addresses cross-site scripting vulnerabilities. The flaw occurs when markdown content containing javascript code is processed by the Open Build Service backend without proper HTML escaping or context-appropriate sanitization. This allows attackers to embed malicious scripts within documentation or project descriptions that execute in the context of other users' browsers when they view the affected pages. The vulnerability's impact extends beyond simple script execution as it compromises both confidentiality and integrity aspects of the system, potentially enabling session hijacking, data exfiltration, and privilege escalation attacks. The persistence of the vulnerability means that malicious code can remain active even after initial injection, continuously affecting users who access the compromised content.
From an operational standpoint, this vulnerability creates substantial risk for organizations using Open Build Service for collaborative software development and build management activities. The remote exploit capability means that attackers can compromise systems without requiring physical access or complex network reconnaissance. The impact on confidentiality is particularly severe as attackers can potentially access sensitive project information, build artifacts, and user credentials stored within the platform. Integrity is compromised through the ability to modify content and inject malicious code that can alter the behavior of web applications. The vulnerability affects not only individual user sessions but can also potentially impact the entire build infrastructure by compromising documentation and project metadata. Security teams must consider that compromised instances may provide attackers with access to development environments and sensitive software artifacts.
Mitigation strategies for CVE-2020-8031 should prioritize immediate deployment of Open Build Service version 2.10.8 or later, which includes proper input sanitization and output encoding fixes. Organizations should implement additional defensive measures such as content security policies that restrict script execution in web contexts, regular security scanning of user-generated content, and enhanced input validation for all markdown processing components. The implementation of web application firewalls and runtime application self-protection mechanisms can provide additional layers of defense against exploitation attempts. Security monitoring should include detection of suspicious markdown content patterns and anomalous user behavior that may indicate exploitation attempts. Regular security assessments and penetration testing of the Open Build Service environment should be conducted to identify potential additional vulnerabilities. The vulnerability also highlights the importance of maintaining up-to-date software versions and implementing robust patch management processes to prevent similar issues from arising in other components of the software supply chain. Organizations should also consider implementing automated content sanitization tools and establishing secure coding practices that prevent similar input validation issues in custom applications that interact with markdown processing functionality.