CVE-2017-7893 in SaltStack Salt
Summary
by MITRE
In SaltStack Salt before 2016.3.6, compromised salt-minions can impersonate the salt-master.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 01/30/2020
The vulnerability identified as CVE-2017-7893 represents a critical security flaw in SaltStack Salt versions prior to 2016.3.6 that fundamentally undermines the integrity of the master-minion communication model. This vulnerability allows compromised salt-minions to potentially impersonate the salt-master, creating a severe attack surface that could enable malicious actors to gain unauthorized control over critical infrastructure management operations. The flaw specifically targets the authentication and identity verification mechanisms within the SaltStack ecosystem, where the security model relies on trust between master and minion components.
The technical implementation of this vulnerability stems from inadequate cryptographic verification processes during the master-minion handshake and authentication phase. When a salt-minion establishes communication with a salt-master, the system should validate the master's identity through robust cryptographic means including digital signatures or secure token exchange mechanisms. However, in vulnerable versions, the minion authentication process fails to properly validate the master's credentials, allowing a compromised minion to present forged authentication tokens or manipulate the communication channel to appear as the legitimate master. This weakness aligns with CWE-287, which addresses improper authentication issues in software systems. The vulnerability essentially creates a man-in-the-middle scenario where the compromised minion can intercept, modify, or forge communications intended for the legitimate salt-master.
The operational impact of CVE-2017-7893 extends far beyond simple privilege escalation, as it enables complete compromise of the SaltStack infrastructure management capabilities. Once an attacker gains control of a salt-minion and exploits this vulnerability, they can execute arbitrary commands across all managed systems within the SaltStack environment, potentially gaining access to sensitive configuration data, system credentials, and operational controls. This threat vector particularly impacts organizations that rely heavily on SaltStack for infrastructure automation and configuration management, as it allows attackers to manipulate deployment schedules, modify system configurations, and potentially escalate privileges to root or administrative levels across the entire network. The attack could be classified under ATT&CK technique T1078 for valid accounts and T1566 for social engineering, though the specific exploitation path involves legitimate authentication mechanisms being subverted rather than traditional social engineering.
Organizations should implement immediate mitigation strategies including upgrading to SaltStack Salt version 2016.3.6 or later, which includes enhanced authentication mechanisms and proper cryptographic verification. Additional protective measures should involve network segmentation to isolate salt-master and salt-minion communications, implementation of network monitoring to detect unusual authentication patterns, and regular security audits of salt-master configurations. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and implementing defense-in-depth strategies, particularly for critical infrastructure management systems. Organizations should also consider implementing additional authentication layers such as certificate-based authentication or multi-factor authentication mechanisms to further protect their SaltStack environments from similar attacks. The remediation process must include comprehensive testing of upgraded systems to ensure that the authentication mechanisms function correctly and that no additional vulnerabilities have been introduced during the update process.