CVE-2018-21030 in Notebook
Summary
by MITRE
Jupyter Notebook before 5.5.0 does not use a CSP header to treat served files as belonging to a separate origin. Thus, for example, an XSS payload can be placed in an SVG document.
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Analysis
by VulDB Data Team • 02/01/2024
The vulnerability identified as CVE-2018-21030 affects Jupyter Notebook versions prior to 5.5.0 and represents a significant security flaw related to cross-site scripting protection mechanisms. This issue stems from the absence of a Content Security Policy (CSP) header implementation within the Jupyter Notebook server, which creates an environment where malicious actors can exploit weaknesses in how served files are treated regarding origin isolation. The lack of proper CSP enforcement allows attackers to inject malicious code that can execute within the context of the user's browser session.
The technical flaw manifests when Jupyter Notebook fails to implement proper CSP headers that would isolate the execution context of served files from the main application domain. This absence creates a scenario where SVG documents, which are often treated as safe due to their image format, can contain malicious XSS payloads that bypass normal security boundaries. When users view these SVG files within the Jupyter environment, the lack of CSP protection means that script execution within the SVG context can interact with the parent notebook application, potentially allowing attackers to execute arbitrary code with the privileges of the logged-in user.
The operational impact of this vulnerability extends beyond simple XSS exploitation, as it enables attackers to perform a range of malicious activities within the compromised Jupyter environment. An attacker could potentially steal user sessions, access sensitive notebooks and data, execute arbitrary commands on the server, or even establish persistence mechanisms. The vulnerability is particularly dangerous in collaborative environments where multiple users access shared Jupyter instances, as it allows an attacker to compromise the entire notebook server and potentially access all user data and computational resources. This flaw aligns with CWE-1021, which specifically addresses Improper Restriction of Rendered UI Layers or Frames, and represents a critical failure in web application security boundary enforcement.
Organizations utilizing Jupyter Notebook should immediately upgrade to version 5.5.0 or later to address this vulnerability, as the fix involves implementing proper CSP headers that separate the origin of served content from the main application context. Additionally, administrators should consider implementing additional security measures such as network segmentation, regular security audits, and monitoring for suspicious file uploads. The mitigation strategy should also include educating users about the risks of opening untrusted files and implementing strict file validation policies. This vulnerability demonstrates the critical importance of proper CSP implementation in web applications and aligns with ATT&CK technique T1203, which covers Exploitation for Client Execution, highlighting how attackers can leverage web application vulnerabilities to execute malicious code in user browsers.