CVE-2021-23732 in docker-cli-js
Summary
by MITRE • 11/22/2021
This affects all versions of package docker-cli-js. If the command parameter of the Docker.command method can at least be partially controlled by a user, they will be in a position to execute any arbitrary OS commands on the host system.
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Analysis
by VulDB Data Team • 11/25/2021
The vulnerability identified as CVE-2021-23732 represents a critical command injection flaw within the docker-cli-js package, a JavaScript library designed to interface with Docker command-line tools. This issue affects all versions of the package and stems from insufficient input validation and sanitization within the Docker.command method implementation. The flaw occurs when user-controllable data is directly incorporated into OS command execution contexts without proper sanitization, creating a pathway for malicious actors to escalate privileges and execute arbitrary commands on the underlying host system. The vulnerability is particularly concerning because it directly undermines the security boundaries that Docker typically maintains between containerized applications and the host environment, effectively allowing attackers to bypass container isolation mechanisms.
The technical exploitation of this vulnerability follows a command injection pattern that aligns with CWE-77 and CWE-88, where user-supplied input flows directly into operating system commands without adequate sanitization. When the Docker.command method receives a command parameter that includes untrusted input, the library fails to properly escape or validate special characters that could alter the intended command execution flow. Attackers can leverage this by crafting malicious input that includes shell metacharacters such as semicolons, ampersands, or backticks, which when processed by the underlying shell, result in unintended command execution. This type of vulnerability is classified as a privilege escalation vector under the MITRE ATT&CK framework, specifically mapping to techniques involving command execution and privilege escalation. The flaw essentially transforms what should be a controlled API call into a potential attack surface that can be exploited to gain full system control.
The operational impact of CVE-2021-23732 extends beyond simple command execution, as it fundamentally compromises the security model of containerized environments. When exploited, attackers can execute arbitrary commands with the privileges of the user running the docker-cli-js application, which often corresponds to the system administrator or application user. This capability allows for complete system compromise including data exfiltration, persistence mechanisms installation, network reconnaissance, and further lateral movement within the network infrastructure. The vulnerability is particularly dangerous in automated build systems, CI/CD pipelines, or applications that utilize docker-cli-js for dynamic container orchestration, as these environments often run with elevated privileges. The attack surface is further expanded when considering that many development and deployment tools rely on JavaScript-based Docker interfaces, making this vulnerability potentially widespread across various DevOps toolchains and container management solutions.
Mitigation strategies for CVE-2021-23732 require immediate action to address the root cause through proper input validation and sanitization practices. Organizations should prioritize updating to the latest version of docker-cli-js where the vulnerability has been patched, as the fix typically involves implementing proper parameter sanitization and escaping mechanisms before command execution. Additionally, implementing strict input validation at multiple layers including API boundaries, application logic, and command execution contexts can significantly reduce exploitation risk. Security teams should also consider implementing network segmentation and privilege separation to limit the impact of potential exploitation, ensuring that applications using docker-cli-js operate with minimal required privileges. The implementation of proper logging and monitoring around Docker command execution can help detect anomalous behavior that may indicate exploitation attempts. Organizations should also review their entire dependency tree to identify other potentially vulnerable packages that may exhibit similar command injection patterns, as this vulnerability type often occurs in libraries that interface with system commands and shell execution environments.