CVE-2018-10099 in Monorail
Summary
by MITRE
Google Monorail before 2018-04-04 has a Cross-Site Search (XS-Search) vulnerability because CSV downloads are affected by CSRF, and calculations of download times (for requests with duplicated columns) can be used to obtain sensitive information about the content of bug reports.
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Analysis
by VulDB Data Team • 04/14/2020
The CVE-2018-10099 vulnerability represents a sophisticated cross-site search attack that exploited weaknesses in Google's Monorail bug tracking system prior to April 4, 2018. This vulnerability falls under the broader category of information disclosure flaws and specifically demonstrates how seemingly innocuous functionality can be weaponized to extract sensitive data. The flaw existed within the CSV download mechanisms of the system, which were susceptible to cross-site request forgery attacks that allowed attackers to manipulate request parameters and observe timing variations in response handling.
The technical exploitation of this vulnerability relied on the manipulation of CSV download requests to trigger specific processing behaviors within the Monorail system. When users requested CSV downloads containing duplicated columns, the system would perform calculations that varied in execution time based on the actual content of the bug reports being processed. Attackers could leverage this timing variation to infer information about the sensitive data contained within the bug reports, effectively creating a timing-based side-channel attack that bypassed traditional access controls. This approach aligns with the CWE-209 classification for information exposure through an error message and demonstrates the complexity of modern web application vulnerabilities.
The operational impact of CVE-2018-10099 was significant as it allowed unauthorized parties to potentially access confidential bug report information that might contain sensitive technical details, security vulnerabilities, or proprietary information. The vulnerability specifically targeted the Google Monorail system, which was used by Google for tracking internal and external bug reports, making it a valuable target for information gathering activities. This type of attack represents a sophisticated approach to information disclosure that leverages the timing characteristics of web application processing rather than traditional injection or authentication bypass techniques.
Mitigation strategies for this vulnerability required addressing both the CSRF protection mechanisms and the timing inconsistencies in the CSV processing logic. The fix implemented by Google involved strengthening CSRF protections for download requests and ensuring that response times remained consistent regardless of the content being processed, thereby eliminating the timing side-channel that enabled the information disclosure. This vulnerability demonstrates the importance of considering timing variations in web application responses and aligns with ATT&CK technique T1213 for data from information repositories, where adversaries seek to extract sensitive information through indirect means rather than direct exploitation of primary vulnerabilities. The remediation approach emphasized the need for consistent response handling and robust cross-site request forgery protections in web applications processing sensitive data.