CVE-2018-19334 in Monorail
Summary
by MITRE
Google Monorail before 2018-05-04 has a Cross-Site Search (XS-Search) vulnerability because CSV downloads are affected by CSRF, and calculations of download times (for requests with an unsupported axis) 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-2018-19334 vulnerability represents a sophisticated cross-site search attack that exploited weaknesses in Google's Monorail bug tracking system prior to May 4, 2018. This vulnerability falls under the broader category of information disclosure flaws and specifically demonstrates how seemingly innocuous features can be weaponized to extract sensitive data. The vulnerability stems from the interaction between CSV download functionality and cross-site request forgery mechanisms, creating an attack vector that allows adversaries to infer confidential information about bug reports through timing analysis.
The technical flaw manifests in how Monorail handled CSV downloads and request processing for unsupported axis parameters. When users requested CSV exports with unsupported axis configurations, the system would calculate download times that varied based on the content of the bug reports being processed. This timing variation created a side-channel attack surface where attackers could measure response times to deduce information about the underlying data structure. The CSRF vulnerability in the CSV download functionality enabled attackers to craft malicious requests that would trigger these timing-sensitive operations without user consent. This combination of factors created a powerful information leakage mechanism that violated fundamental security principles of data isolation and access control.
The operational impact of this vulnerability was significant as it allowed attackers to perform reconnaissance and information gathering against Google's internal bug tracking system. Adversaries could potentially extract sensitive details about security vulnerabilities, internal project information, or other confidential data contained within bug reports. The vulnerability was particularly concerning because it operated at the application level and could be exploited through web-based attacks without requiring privileged access or specialized hardware. This made it an attractive target for threat actors seeking to understand Google's internal security processes or identify potential targets for further exploitation. The vulnerability also highlighted the importance of considering timing-based side-channel attacks in web application security assessments.
Mitigation strategies for CVE-2018-19334 should focus on implementing proper input validation and CSRF protection mechanisms while eliminating timing variations that could leak information. Organizations should ensure that all download operations are protected by robust CSRF tokens and that response times remain consistent regardless of content. The fix implemented by Google likely involved strengthening CSRF protections for CSV download endpoints and normalizing the response time behavior for requests with unsupported parameters. Security practitioners should reference CWE-352 for cross-site request forgery vulnerabilities and CWE-203 for information leakage through timing variations. This vulnerability also aligns with ATT&CK technique T1213.002 for data from information repositories, demonstrating how web application flaws can enable information gathering operations. The incident underscores the necessity of comprehensive security testing including side-channel attack simulations and proper input sanitization to prevent similar vulnerabilities in web applications.