CVE-2021-3148 in SaltStack Salt
Summary
by MITRE • 02/27/2021
An issue was discovered in SaltStack Salt before 3002.5. Sending crafted web requests to the Salt API can result in salt.utils.thin.gen_thin() command injection because of different handling of single versus double quotes. This is related to salt/utils/thin.py.
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Analysis
by VulDB Data Team • 03/14/2021
The vulnerability identified as CVE-2021-3148 represents a critical command injection flaw within the SaltStack Salt configuration management platform affecting versions prior to 3002.5. This security weakness resides in the salt.utils.thin.gen_thin() function which is responsible for generating thin components used in Salt's remote execution capabilities. The vulnerability stems from improper handling of quote characters during the processing of web requests sent to the Salt API, creating an avenue for malicious actors to execute arbitrary commands on affected systems. The flaw specifically manifests when crafted web requests are submitted to the Salt API endpoint, exploiting inconsistencies in how single and double quotes are processed within the command generation logic.
The technical implementation of this vulnerability can be traced to the salt/utils/thin.py module where the gen_thin() function fails to properly sanitize user input containing quote characters. When the Salt API receives web requests with maliciously crafted parameters, the function processes these inputs without adequate validation or escaping mechanisms. This improper handling allows attackers to inject shell commands that are subsequently executed by the system. The vulnerability is categorized under CWE-78 as a "Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')" which is a well-established class of vulnerabilities that has been extensively documented in security frameworks. The specific nature of this injection occurs due to insufficient input validation and improper shell command construction within the thin component generation process.
The operational impact of CVE-2021-3148 is severe and far-reaching for organizations utilizing SaltStack Salt in production environments. Attackers who successfully exploit this vulnerability can achieve arbitrary code execution on systems running vulnerable Salt master or minion components, potentially leading to complete system compromise. The attack surface is particularly concerning given that SaltStack is commonly used for infrastructure automation, configuration management, and remote system administration across enterprise networks. This vulnerability allows threat actors to escalate privileges, exfiltrate sensitive data, deploy malware, or establish persistent backdoors within the network infrastructure. The implications extend beyond individual system compromise as SaltStack typically manages large numbers of systems, making a successful exploitation potentially devastating for entire organizations. Organizations may face compliance violations, data breaches, and significant operational disruption when this vulnerability is exploited.
Mitigation strategies for CVE-2021-3148 primarily focus on upgrading to SaltStack Salt version 3002.5 or later where the vulnerability has been addressed through improved input validation and quote handling mechanisms. Organizations should also implement network segmentation and access controls to limit exposure of the Salt API endpoints to trusted networks only. Additional defensive measures include monitoring API traffic for suspicious patterns, implementing web application firewalls to detect and block malicious requests, and conducting regular security assessments of SaltStack configurations. The ATT&CK framework categorizes this vulnerability under T1059.001 "Command and Scripting Interpreter: PowerShell" and T1059.003 "Command and Scripting Interpreter: Windows Command Shell" as it enables adversaries to execute arbitrary commands through the compromised Salt API interface. Security teams should also consider implementing automated patch management processes to ensure timely deployment of security updates and maintain visibility into the attack surface through continuous monitoring of SaltStack environments.