CVE-2023-24531: Go Environment Command RCE Vulnerability

CVE-2023-24531 Overview

CVE-2023-24531 is a command injection vulnerability in the Go programming language's go env command. The command is documented as outputting a shell script containing the Go environment configuration. However, go env fails to properly sanitize values, which means executing its output as a shell script can result in various malicious behaviors, including arbitrary command execution or injection of new environment variables.

Critical Impact

Attackers who can influence environment variables on a target system can leverage this vulnerability to execute arbitrary commands when the output of go env is evaluated as a shell script.

Affected Products

• Go programming language toolchain
• Applications and scripts that evaluate go env output as shell commands
• Systems where Go development tools are installed and environment output is processed

Discovery Timeline

• 2024-07-02 - CVE CVE-2023-24531 published to NVD
• 2025-03-28 - Last updated in NVD database

Technical Details for CVE-2023-24531

Vulnerability Analysis

The vulnerability stems from a failure to properly sanitize environment variable values before including them in the shell script output generated by the go env command. When developers or automation scripts execute this output directly in a shell context (such as eval $(go env) or similar patterns), unsanitized values containing shell metacharacters can break out of their intended context and execute arbitrary commands.

This type of vulnerability is particularly dangerous in continuous integration/continuous deployment (CI/CD) pipelines and build systems where Go environment configuration is commonly sourced from go env output. An attacker who can manipulate environment variables—through compromised upstream dependencies, malicious repository configurations, or other means—could inject shell commands that execute during the build process.

The vulnerability allows for network-based exploitation without requiring authentication or user interaction, making it potentially exploitable in automated environments where environment variables may be influenced by external sources.

Root Cause

The root cause is an input validation error in the go env command's output generation logic. The command generates shell-compatible output (environment variable assignments) but fails to escape or sanitize special shell characters within the variable values. This allows shell metacharacters such as backticks, $() command substitution, semicolons, and other shell operators to be interpreted when the output is executed.

Attack Vector

The attack vector involves manipulating environment variables that are subsequently output by go env. When a victim script or automation process evaluates this output as a shell script, the injected commands execute with the privileges of the running process. Attack scenarios include:

1. CI/CD Pipeline Compromise: Malicious environment variables set through build configurations or compromised dependencies get executed during builds that source go env output
2. Developer Workstation Attacks: If an attacker can influence environment variables on a developer's machine (through malicious Git configurations, compromised tools, etc.), running common Go development patterns could trigger code execution
3. Supply Chain Attacks: Compromised development tools or scripts that set environment variables before invoking go env could inject commands

The Go team has addressed this through code changes documented in Go CL 488375 and Go CL 493535, which implement proper sanitization of values in the shell script output.

Detection Methods for CVE-2023-24531

Indicators of Compromise

• Unusual environment variables containing shell metacharacters (backticks, $(), semicolons, pipes)
• Unexpected command execution during Go build processes or environment setup
• Anomalous process spawning from Go toolchain-related parent processes
• Modified Go environment configuration files with suspicious content

Detection Strategies

• Monitor for execution of go env output through shell evaluation patterns (eval, source, or backtick execution)
• Implement file integrity monitoring on Go installation directories and configuration files
• Analyze CI/CD pipeline logs for unexpected command execution during Go environment setup phases
• Deploy endpoint detection rules to identify command injection patterns in environment variables

Monitoring Recommendations

• Enable verbose logging for Go toolchain operations in build environments
• Implement runtime application self-protection (RASP) monitoring for shell command execution
• Configure SIEM rules to alert on unusual process trees originating from Go-related processes
• Establish baseline behavior for Go build processes and alert on deviations

How to Mitigate CVE-2023-24531

Immediate Actions Required

• Upgrade Go toolchain to a patched version that properly sanitizes go env output
• Review and audit scripts and automation that evaluate go env output as shell commands
• Implement environment variable validation before sourcing Go environment configuration
• Consider alternative approaches such as parsing go env -json output instead of shell evaluation

Patch Information

The Go team has released fixes through multiple code changes. Refer to Go Issue 58508 for the official vulnerability tracking and Go Vulnerability Report GO-2024-2962 for detailed patch information. NetApp has also published a Security Advisory regarding affected products.

Workarounds

• Avoid evaluating go env output directly as shell commands; instead use go env -json and parse the JSON output programmatically
• Implement strict input validation on environment variables before any Go toolchain operations
• Run Go build processes in isolated environments with minimal environment variable exposure
• Use containerization or sandboxing to limit the impact of potential command execution

# Safer alternative: Use JSON output instead of shell evaluation
# Instead of: eval $(go env)
# Use JSON parsing with jq or similar tools:
go env -json | jq -r 'to_entries | .[] | "export \(.key)=\(.value | @sh)"' | while read line; do
    # Validate each line before execution
    echo "$line"
done