CVE-2021-36795 in Cohesity
Summary
by MITRE • 08/07/2021
A permission issue in the Cohesity Linux agent may allow privilege escalation in version 6.5.1b to 6.5.1d-hotfix10, 6.6.0a to 6.6.0b-hotfix1. An underprivileged linux user, if certain environment criteria are met, can gain additional privileges.
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Analysis
by VulDB Data Team • 08/10/2021
The vulnerability identified as CVE-2021-36795 represents a critical permission flaw within the Cohesity Linux agent software ecosystem. This issue affects specific versions of the Cohesity backup and data management platform, namely releases 6.5.1b through 6.5.1d-hotfix10 and 6.6.0a through 6.6.0b-hotfix1. The flaw manifests as an insufficient access control mechanism that allows unauthorized users to escalate their privileges within the system. The vulnerability operates at the intersection of improper privilege management and inadequate security controls, creating a pathway for malicious actors to gain elevated system access.
The technical implementation of this vulnerability stems from improper handling of user permissions within the Cohesity agent software. When specific environmental conditions are met, the agent fails to properly validate user credentials and access levels, allowing a low-privilege user to execute commands with elevated privileges. This permission bypass occurs through a combination of weak access controls and potentially flawed privilege separation mechanisms. The vulnerability is particularly concerning because it operates silently without requiring additional exploitation vectors, making detection more challenging for security monitoring systems.
The operational impact of this privilege escalation vulnerability extends beyond simple unauthorized access, potentially enabling full system compromise and data exfiltration. An attacker who successfully exploits this vulnerability can gain root-level access to systems running the affected Cohesity agent versions, providing complete control over backup operations, data access, and system resources. This escalation capability allows for persistent access, data manipulation, and potential lateral movement within the network infrastructure. The vulnerability's impact is amplified when considering that Cohesity agents are typically deployed in enterprise environments where they have significant access to critical data and system resources.
Security professionals should implement immediate mitigations including upgrading to patched versions of the Cohesity software, implementing strict access controls for agent installations, and monitoring for unauthorized privilege escalation attempts. The vulnerability aligns with CWE-276, which addresses improper privilege management, and represents a clear violation of the principle of least privilege. Organizations should conduct comprehensive assessments of their Cohesity deployments, verify the installed versions against known vulnerable releases, and implement network segmentation to limit potential attack surfaces. Additionally, monitoring for unusual privilege escalation activities and implementing robust audit logging for agent operations can help detect exploitation attempts. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting the use of software vulnerabilities to gain elevated system access. Organizations must also consider the broader implications for their backup and recovery infrastructure, as compromised Cohesity agents could provide attackers with access to critical backup data and potentially enable more sophisticated attacks such as ransomware operations.