WSL Node & Npm Setup Behind SSL Decrypt

WSL Node/npm Setup Behind SSL Interception

wsl nodejs npm ssl development

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Goal

• Use Node.js via nvm inside WSL
• Allow npm install to succeed behind a corporate SSL-inspecting firewall using self-signed root/intermediate CAs

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Install Node 20+ with nvm

# Install nvm (if not present)
curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/master/install.sh | bash
source ~/.nvm/nvm.sh
 
# Install and use Node 20+
nvm install 20
nvm use 20
nvm alias default 20
 
# Verify
node -v
npm -v

Ensures you’re using a user-owned Node install (under ~/.nvm/versions/...).

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Remove Conflicting npm Prefix Settings

# Remove old npm prefix/globalconfig overrides
sed -i '/^prefix=/d;/^globalconfig=/d' ~/.npmrc 2>/dev/null || true
npm config delete prefix || true
npm config delete globalconfig || true
 
# Confirm nvm paths are correct
npm prefix -g    # ~/.nvm/versions/node/v20.x.x
npm root -g      # ~/.nvm/versions/node/v20.x.x/lib/node_modules

Prevents permission errors (EACCES) from using /usr/local/lib.

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Import Corporate CA Certificates

# Place certs in ~/.certs (PEM/CRT format)
mkdir -p ~/.certs
# Copy your corporate root and intermediate CA .crt files here
 
# Install into system trust store
sudo mkdir -p /usr/local/share/ca-certificates/extra
sudo cp ~/.certs/*.crt /usr/local/share/ca-certificates/extra
sudo update-ca-certificates

Expect output: N added, 0 removed (where N = number of certs).

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Bundle CAs for Node/npm

# Create a single bundle
cat /usr/local/share/ca-certificates/extra/*.crt > ~/.certs/corp-bundle.crt
 
# Node (nvm-safe)
echo 'export NODE_EXTRA_CA_CERTS="$HOME/.certs/corp-bundle.crt"' >> ~/.bashrc
 
# npm
npm config set cafile "$HOME/.certs/corp-bundle.crt"
npm config set strict-ssl true
 
# Reload shell to apply
exec bash -l

Makes Node.js and npm trust your corporate CA without disabling SSL verification.

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Verify and Install

# Should NOT show cert errors
curl -sI https://api.github.com | head -n1
 
# Confirm config
echo $NODE_EXTRA_CA_CERTS
npm config get cafile
 
# Test install
npm install -g <some-package>

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Git Configuration (Optional)

git config --global http.sslCAInfo "$HOME/.certs/corp-bundle.crt"

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Quick Troubleshooting Table

Problem	Likely Fix
SELF_SIGNED_CERT_IN_CHAIN	Missing root/intermediate in trust store
0 added, 0 removed on update-ca-certificates	Rename .pem → .crt and ensure CA:TRUE
EACCES on npm global install	Remove prefix from ~/.npmrc; use nvm
command not found for node/npm	Add nvm init to ~/.bashrc