Security: Supply chain risk — curl-to-bash install without integrity verification

[hendrixfreire]

Vulnerability Description

The README recommends installing the skill via a one-liner that pipes curl directly to bash:

curl -fsSL https://raw.githubusercontent.com/AgriciDaniel/claude-ads/main/install.sh | bash

This pattern has known supply chain risks:

1. No integrity verification — if the GitHub CDN (raw.githubusercontent.com) is compromised or the connection is MITM'd, the script executed could be malicious
2. Truncation attacks — if the TCP connection drops mid-download, bash executes a partial script (though set -euo pipefail in the script partially mitigates this)
3. No signature/checksum — there is no way to verify the script is authentic

Impact

• Severity: Medium (supply chain)
• A compromised raw.githubusercontent.com response or MITM attacker could execute arbitrary code on the user's machine
• Affects every user who follows the recommended install method

Real-World Precedent

Similar attacks have occurred:

• Polygon Network (2021): GitHub CDN compromise
• Multiple npm packages (various): supply chain attacks via install scripts

Proposed Fix

Option A: Add SHA256 checksum to README (simplest)

# Download and verify before executing
curl -fsSLo install.sh https://raw.githubusercontent.com/AgriciDaniel/claude-ads/main/install.sh
echo "abc123def456...  install.sh" | sha256sum -c
bash install.sh

Generate checksum in CI/CD and update README on each release.

Option B: Recommend git clone + local install (most secure)

git clone https://github.com/AgriciDaniel/claude-ads
cd claude-ads
bash install.sh

Option C: GitHub Releases with signed assets

Publish install.sh as a release asset and sign it with GPG.

Additional Context

• The install.sh script itself is well-written (set -euo pipefail, main function wrapper, trap for cleanup)
• The script clones from the same repo — so the clone step has integrity via git's cryptographic verification
• The risk is only in the initial bootstrap via curl | bash

Found during a full security audit of the repository.