CVE-2021-45101 in HTCondor
Summary
by MITRE • 12/16/2021
An issue was discovered in HTCondor before 8.8.15, 9.0.x before 9.0.4, and 9.1.x before 9.1.2. Using standard command-line tools, a user with only READ access to an HTCondor SchedD or Collector daemon can discover secrets that could allow them to control other users' jobs and/or read their data.
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Analysis
by VulDB Data Team • 12/18/2021
The vulnerability identified as CVE-2021-45101 represents a significant privilege escalation and information disclosure flaw within the HTCondor distributed computing system. This issue affects multiple versions of HTCondor including the 8.8.15 release and earlier, 9.0.4 and earlier in the 9.0.x series, and 9.1.2 and earlier in the 9.1.x series. HTCondor is widely deployed in high-performance computing environments for job scheduling and resource management, making this vulnerability particularly concerning for organizations relying on its security controls. The flaw specifically targets the authentication and authorization mechanisms of HTCondor's SchedD (scheduler) and Collector daemons, which are fundamental components responsible for job scheduling and system monitoring respectively.
The technical implementation of this vulnerability stems from insufficient access control validation within the command-line tools used to interact with HTCondor daemons. A user with only READ access privileges can exploit this weakness to extract sensitive information from the system that should normally be restricted to administrators or users with higher privileges. This occurs because the system fails to properly enforce authorization checks when processing certain commands, allowing unauthorized users to discover authentication tokens, job credentials, and other sensitive data that could be used to impersonate other users or access confidential job information. The vulnerability manifests through the improper handling of privilege levels during command execution, creating a pathway for information leakage that violates fundamental security principles of least privilege and access control enforcement.
The operational impact of CVE-2021-45101 extends beyond simple information disclosure to encompass potential complete system compromise. An attacker with READ access can leverage this vulnerability to gain control over other users' jobs, effectively enabling them to modify, terminate, or manipulate computational tasks that they should not have access to. This capability undermines the core security model of HTCondor systems where job isolation and user privacy are paramount. The vulnerability also exposes sensitive data that could include proprietary research, personal information, or confidential computational results. From an attack perspective, this vulnerability aligns with attack techniques categorized under credential access and privilege escalation in the MITRE ATT&CK framework, specifically mapping to techniques such as "T1550 - Use Alternate Authentication Material" and "T1078 - Valid Accounts." The weakness also corresponds to CWE-284, which describes improper access control, and CWE-276, which addresses improper privileges.
Organizations affected by this vulnerability should implement immediate mitigations including upgrading to the patched versions of HTCondor where available. The recommended remediation strategy involves applying the security patches released by the HTCondor project, specifically versions 8.8.15, 9.0.4, and 9.1.2, which contain the necessary fixes for the access control bypass. Additionally, system administrators should review and tighten access controls for HTCondor daemons, ensuring that users have only the minimum necessary privileges required for their legitimate operations. Network segmentation and firewall rules should be implemented to restrict direct access to HTCondor daemons from untrusted networks. Monitoring and logging should be enhanced to detect unusual command-line activity that might indicate exploitation attempts. Organizations should also consider implementing additional security controls such as mandatory access controls or role-based access control mechanisms that provide defense-in-depth against similar vulnerabilities. The vulnerability highlights the importance of proper authorization checking in distributed computing systems and serves as a reminder that even read-only users should not be able to extract sensitive information that could enable further attacks.