CVE-2018-7187 in Google
Summary
by MITRE
The "go get" implementation in Go 1.9.4, when the -insecure command-line option is used, does not validate the import path (get/vcs.go only checks for "://" anywhere in the string), which allows remote attackers to execute arbitrary OS commands via a crafted web site.
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Analysis
by VulDB Data Team • 02/08/2023
The vulnerability described in CVE-2018-7187 represents a critical command injection flaw within the go get functionality of the Go programming language version 1.9.4. This issue specifically manifests when developers utilize the -insecure command-line option during package retrieval operations. The vulnerability stems from inadequate input validation within the version control system implementation, where the code in get/vcs.go performs a superficial check for the presence of "://" anywhere within the import path string without proper sanitization or validation of the complete path structure. This design flaw creates an exploitable condition that allows remote attackers to manipulate the command execution flow through carefully crafted web sites that can be processed by the vulnerable go get implementation.
The technical exploitation of this vulnerability occurs through a command injection attack vector where malicious actors can craft import paths that bypass the intended validation mechanisms. When the -insecure flag is used, the go get command becomes more permissive in its handling of remote sources, but this permissiveness is exploited by attackers who construct import paths containing malicious command sequences that get executed as operating system commands. The flaw lies in the improper parsing and validation of the import path, allowing attackers to inject command separators or other malicious constructs that get interpreted by the underlying shell or command execution layer. This vulnerability directly maps to CWE-78 which describes improper neutralization of special elements used in OS commands, and represents a classic example of command injection where user-controllable input is directly incorporated into system commands without proper sanitization.
The operational impact of CVE-2018-7187 extends beyond simple command execution, as it allows attackers to gain arbitrary code execution capabilities on systems where vulnerable Go versions are installed. This could enable attackers to access sensitive system resources, exfiltrate data, install backdoors, or perform other malicious activities. The vulnerability is particularly concerning in development environments where go get is frequently used with the -insecure flag, as it provides an attack surface that can be exploited through compromised websites or malicious package repositories. The attack requires minimal privileges to execute successfully and can be automated through web-based delivery mechanisms, making it a significant threat to organizations that rely on Go package management. According to ATT&CK framework, this vulnerability aligns with T1059.001 (Command and Scripting Interpreter: PowerShell) and T1068 (Exploitation for Privilege Escalation) techniques, as it enables attackers to execute arbitrary commands on target systems.
Mitigation strategies for CVE-2018-7187 involve immediate remediation through upgrading to Go versions that have patched this vulnerability, specifically versions 1.10 or later where the import path validation has been strengthened. Organizations should also avoid using the -insecure flag in production environments unless absolutely necessary, as this flag disables important security checks. Additional protective measures include implementing network segmentation to limit access to trusted package repositories, monitoring for suspicious go get operations, and conducting regular security audits of development environments. Security teams should also consider implementing application whitelisting policies that restrict which commands can be executed by the go get functionality, and establish proper input validation controls within their development workflows to prevent the use of untrusted import paths. The vulnerability underscores the importance of proper input validation and the principle of least privilege in security implementations, as the flaw could be exploited by attackers who gain access to compromised websites or by manipulating the Go package management workflow.