CVE-2018-12104 in Knowledge Repo
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Airbnb Knowledge Repo 0.7.4 allows remote attackers to inject arbitrary web scripts or HTML via the post comments functionality, as demonstrated by the post/posts/new_report.kp URI.
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Analysis
by VulDB Data Team • 03/27/2023
The CVE-2018-12104 vulnerability represents a critical cross-site scripting flaw discovered in Airbnb's Knowledge Repo version 0.7.4, specifically targeting the post comments functionality. This vulnerability exposes the application to remote code execution risks where malicious actors can inject arbitrary web scripts or HTML content directly into the platform's comment system. The attack vector is particularly concerning as it leverages the post/posts/new_report.kp URI endpoint, which serves as a legitimate pathway for users to create new reports within the knowledge repository framework. The vulnerability stems from inadequate input validation and output encoding mechanisms within the application's comment processing pipeline, allowing attackers to bypass security controls that should normally sanitize user-submitted content before rendering it on web pages.
The technical exploitation of this vulnerability occurs when an attacker crafts malicious input containing script tags or other HTML elements within the comment fields of posts. When other users view these comments, the injected scripts execute in their browsers within the context of the vulnerable application, potentially enabling session hijacking, credential theft, or redirection to malicious sites. The flaw specifically manifests in the application's failure to properly escape or sanitize special characters in user-provided comments, creating an environment where attacker-controlled content can be interpreted as executable code rather than plain text. This issue falls under CWE-79 which categorizes improper neutralization of input during web page generation, representing one of the most common and dangerous web application vulnerabilities. The vulnerability's impact is amplified by the fact that Knowledge Repo applications typically serve as collaborative platforms where multiple users interact with shared content, making the potential attack surface broad and the damage multiplier significant.
From an operational perspective, this vulnerability poses severe risks to organizations relying on the Knowledge Repo platform for internal documentation and knowledge sharing. The attack scenario involves an attacker posting malicious comments to existing posts or creating new posts with injected scripts, which then execute whenever other users access these content areas. The consequences extend beyond simple data theft to include potential complete system compromise through session manipulation, data exfiltration, and the establishment of persistent backdoors. The vulnerability affects the platform's integrity and trust model, as users may unknowingly execute malicious code while browsing seemingly legitimate content. Organizations using this software face potential regulatory compliance issues, as the vulnerability creates opportunities for unauthorized access and data breaches that could violate data protection standards such as gdpr or hipaa. The ATT&CK framework categorizes this vulnerability under T1059.007 for scripting languages and T1566 for credential access through social engineering, highlighting both the execution and persistence aspects of the threat.
Mitigation strategies for CVE-2018-12104 require immediate implementation of comprehensive input sanitization and output encoding measures. Organizations should implement strict validation of all user inputs through whitelisting approaches, ensuring that only expected characters and formats are accepted in comment fields. The application must employ proper HTML escaping mechanisms before rendering any user-provided content, preventing script execution through the use of libraries such as html.escape or equivalent security functions. Additionally, implementing content security policies with strict directives can prevent unauthorized script execution even if input validation is bypassed. Regular security updates and patches should be applied immediately upon availability, as the vulnerability affects a specific version of the software. Implementing web application firewalls with XSS detection capabilities and conducting regular security assessments including automated scanning and manual penetration testing can help identify similar vulnerabilities in the codebase. The solution should also include proper logging and monitoring of user activities, particularly around comment creation and modification, to detect anomalous behavior that may indicate exploitation attempts. Organizations should establish secure coding practices and conduct regular security training for developers to prevent similar vulnerabilities in future releases.