CVE-2017-1000037 in RVM
Summary
by MITRE
RVM automatically loads environment variables from files in $PWD resulting in command execution RVM vulnerable to command injection when automatically loading environment variables from files in $PWD RVM automatically executes hooks located in $PWD resulting in code execution RVM automatically installs gems as specified by files in $PWD resulting in code execution RVM automatically does "bundle install" on a Gemfile specified by .versions.conf in $PWD resulting in code execution
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Analysis
by VulDB Data Team • 10/26/2019
The vulnerability identified as CVE-2017-1000037 affects the Ruby Version Manager (RVM) system, presenting a critical command injection flaw that stems from RVM's automatic processing of files within the current working directory. This vulnerability operates through multiple attack vectors that collectively enable arbitrary code execution, making it particularly dangerous for developers and system administrators who rely on RVM for Ruby environment management. The flaw exists because RVM automatically parses and executes content from various configuration files located in the current directory without proper sanitization or validation of the input data.
The technical exploitation of this vulnerability occurs when RVM encounters specific files in the $PWD directory, including but not limited to .rvmrc, .versions.conf, and Gemfile files. When these files contain malicious content, RVM's automatic processing mechanism executes the embedded commands with the privileges of the user running the RVM command. This behavior aligns with CWE-78, which describes improper neutralization of special elements used in OS commands, and CWE-94, which covers inadequate control of generation of code. The vulnerability essentially allows an attacker to inject malicious commands that get executed within the context of the RVM process, potentially leading to full system compromise.
The operational impact of this vulnerability extends beyond simple code execution, as it can enable attackers to perform privilege escalation, data exfiltration, and persistent access to affected systems. Attackers can leverage this vulnerability by placing malicious files in directories where RVM is executed, particularly in development environments where users frequently change directories. The automatic nature of the execution means that simply navigating to a compromised directory can trigger the attack, making it particularly stealthy and difficult to detect. This vulnerability also affects the principle of least privilege by allowing unauthorized code execution without explicit user consent or awareness, which violates fundamental security practices outlined in the NIST Cybersecurity Framework.
Mitigation strategies for this vulnerability include immediate patching of RVM installations to versions that address the automatic file processing behavior, implementing proper file access controls and directory permissions, and disabling automatic RVM environment loading through configuration changes. Organizations should also consider implementing directory-based security controls that restrict execution of potentially malicious files in development environments. The ATT&CK framework categorizes this vulnerability under T1059.001 for command and scripting interpreter and T1068 for exploit for privilege escalation, emphasizing the need for comprehensive security controls. Additionally, implementing proper input validation and sanitization mechanisms, using sandboxed environments for RVM operations, and conducting regular security audits of development environments can significantly reduce the risk exposure associated with this vulnerability.