CVE-2020-1887 in osquery
Summary
by MITRE
Incorrect validation of the TLS SNI hostname in osquery versions after 2.9.0 and before 4.2.0 could allow an attacker to MITM osquery traffic in the absence of a configured root chain of trust.
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Analysis
by VulDB Data Team • 04/16/2024
The vulnerability identified as CVE-2020-1887 represents a critical flaw in osquery's handling of TLS Server Name Indication (SNI) hostname validation within versions ranging from 2.9.1 through 4.1.9. This issue stems from insufficient validation of the SNI field during TLS handshake processes, creating a potential attack vector for man-in-the-middle scenarios. The flaw specifically affects systems where osquery is configured to communicate over TLS without a properly established root certificate chain of trust, leaving network traffic susceptible to interception and manipulation. The vulnerability operates at the application layer and directly impacts the integrity of secure communications between osquery clients and their remote endpoints.
The technical implementation of this vulnerability resides in the certificate validation logic within osquery's TLS stack where the SNI hostname is not properly validated against the certificate presented by the server. This weakness allows an attacker to potentially present a certificate that matches the SNI value but does not correspond to the actual server identity, effectively bypassing certificate validation mechanisms. The flaw is categorized under CWE-295 which specifically addresses improper certificate validation and weak certificate chain validation. When osquery processes TLS connections without a configured trust chain, it becomes vulnerable to attacks where malicious actors can intercept traffic by presenting certificates that pass SNI validation but fail proper certificate verification. This represents a fundamental breakdown in the certificate trust model that osquery relies upon for secure communication channels.
The operational impact of this vulnerability extends beyond simple network monitoring implications to potentially compromise the integrity of endpoint detection and response systems. Attackers leveraging this vulnerability could intercept and manipulate osquery data collection processes, potentially altering or suppressing security events that would otherwise be transmitted to security operations centers. The vulnerability particularly affects environments where osquery is used for threat hunting, compliance monitoring, or security analytics, as compromised communication channels could lead to undetected security incidents. This flaw aligns with ATT&CK technique T1071.001 for Application Layer Protocol: Web Protocols and T1566 for Phishing, as it enables attackers to establish persistent communication channels that could evade traditional network monitoring controls. Organizations relying on osquery for security operations may experience data integrity issues and potential compromise of their security posture.
Mitigation strategies for CVE-2020-1887 primarily focus on upgrading to osquery version 4.2.0 or later where the SNI validation has been properly addressed. System administrators should also ensure that all osquery configurations include proper root certificate chain validation and implement certificate pinning where appropriate. Network segmentation and monitoring of osquery communication patterns can help detect potential exploitation attempts. The vulnerability demonstrates the critical importance of maintaining current software versions and implementing robust certificate management practices. Organizations should also consider implementing additional layers of security monitoring such as network protocol analysis and anomaly detection to identify potential MITM activities. Regular security assessments of endpoint monitoring tools and their communication channels should be conducted to prevent similar vulnerabilities from compromising security operations. The fix implemented in version 4.2.0 specifically addresses the certificate validation logic and ensures that SNI hostname validation properly integrates with the broader certificate trust validation mechanisms.