Poshan Pandey
82 lines
2.8 KiB
Bash
82 lines
2.8 KiB
Bash
#!/bin/bash
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# Scans file content for accidental secrets before writing.
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# Used as a PreToolUse hook for Edit|Write operations.
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# Exit 2 = block. Exit 0 = allow.
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# Requires jq for JSON parsing — allow if missing (don't block the user)
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if ! command -v jq >/dev/null 2>&1; then
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exit 0
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fi
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INPUT=$(cat)
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TOOL_NAME=$(echo "$INPUT" | jq -r '.tool_name // empty')
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# Extract the content being written
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if [ "$TOOL_NAME" = "Write" ]; then
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CONTENT=$(echo "$INPUT" | jq -r '.tool_input.content // empty')
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elif [ "$TOOL_NAME" = "Edit" ]; then
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CONTENT=$(echo "$INPUT" | jq -r '.tool_input.new_string // empty')
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else
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exit 0
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fi
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if [ -z "$CONTENT" ]; then
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exit 0
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fi
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# --- High-confidence secret patterns ---
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MATCHES=""
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# AWS Access Key IDs
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if echo "$CONTENT" | grep -qE 'AKIA[0-9A-Z]{16}'; then
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MATCHES="$MATCHES AWS access key (AKIA...);"
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fi
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# AWS Secret Access Keys (40 chars base64 after a key assignment)
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if echo "$CONTENT" | grep -qiE '(aws_secret_access_key|secret_key)[[:space:]]*[=:][[:space:]]*["\x27]?[A-Za-z0-9/+=]{40}'; then
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MATCHES="$MATCHES AWS secret key;"
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fi
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# GitHub tokens (PAT, OAuth, App)
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if echo "$CONTENT" | grep -qE '(ghp_|gho_|ghs_|ghr_|github_pat_)[a-zA-Z0-9_]{20,}'; then
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MATCHES="$MATCHES GitHub token;"
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fi
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# OpenAI / Stripe / Anthropic style keys (sk-...)
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if echo "$CONTENT" | grep -qE 'sk-[a-zA-Z0-9]{20,}'; then
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MATCHES="$MATCHES API key (sk-...);"
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fi
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# Slack tokens
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if echo "$CONTENT" | grep -qE 'xox[bpras]-[0-9a-zA-Z-]{10,}'; then
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MATCHES="$MATCHES Slack token;"
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fi
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# Private key blocks
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if echo "$CONTENT" | grep -qE -- '-----BEGIN[[:space:]]+(RSA |EC |DSA |OPENSSH )?PRIVATE KEY-----'; then
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MATCHES="$MATCHES private key block;"
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fi
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# Connection strings with embedded credentials
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if echo "$CONTENT" | grep -qE '(mongodb|postgres|mysql|redis|amqp|smtp)(\+[a-z]+)?://[^:[:space:]]+:[^@[:space:]]+@'; then
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MATCHES="$MATCHES connection string with credentials;"
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fi
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# Generic password/secret/token assignments with literal string values
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# Matches: password = "actual_value", SECRET_KEY: 'actual_value', api_token="actual_value"
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# Excludes: env var references like process.env.*, os.environ.*, ${...}, getenv(...)
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if echo "$CONTENT" | grep -qiE '(password|secret|token|api_key|apikey|api_secret)[[:space:]]*[=:][[:space:]]*["\x27][^"\x27]{8,}["\x27]' && \
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! echo "$CONTENT" | grep -qiE '(password|secret|token|api_key|apikey|api_secret)[[:space:]]*[=:][[:space:]]*["\x27]?(process\.env|os\.environ|getenv|\$\{|ENV\[|env\()'; then
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MATCHES="$MATCHES hardcoded credential;"
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fi
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if [ -n "$MATCHES" ]; then
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# Use "ask" not "deny" — warn the user but let them override (could be test fixtures)
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REASON="Possible secret detected in content:$MATCHES Review carefully before allowing."
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echo "{\"hookSpecificOutput\":{\"hookEventName\":\"PreToolUse\",\"permissionDecision\":\"ask\",\"permissionDecisionReason\":\"$REASON\"}}"
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exit 2
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fi
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exit 0
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