# PR #461 - Supply Chain Vulnerability Acceptance ## Summary Supply chain security scans for PR #461 identified **9 vulnerabilities** in Alpine Linux 3.23.0 base image packages. After thorough risk assessment, all vulnerabilities are **accepted** pending upstream Alpine Security Team patches. **Key Points**: - ✅ **Application Code**: 0 vulnerabilities (clean) - ⚠️ **Alpine Base Image**: 9 CVEs (8 MEDIUM + 1 LOW) - 🛡️ **Risk Level**: LOW overall (containerized deployment + no attack surface exposure) - 📅 **Review Date**: 2026-02-13 (30 days) --- ## Vulnerability Breakdown ### busybox (3 packages) - CVE-2025-60876 - **Severity**: MEDIUM - **Packages**: busybox, busybox-binsh, ssl_client (1.37.0-r20) - **Type**: Heap buffer overflow - **Exploitability**: LOW (requires local shell access) - **Impact**: LOW (no shell access exposed through Charon) **Why Acceptable**: - Charon does not expose shell access to users - Container runs as non-root user with minimal privileges - Container isolation provides defense-in-depth - No busybox commands accept user input through application APIs ### curl (7 CVEs) - Multiple Issues - **CVE-2025-15079** (MEDIUM): HTTP/2 DoS - Loop/resource exhaustion - **CVE-2025-14819** (MEDIUM): TLS certificate validation bypass - **CVE-2025-14524** (MEDIUM): Cookie handling information exposure - **CVE-2025-13034** (MEDIUM): URL parsing injection/filter bypass - **CVE-2025-10966** (MEDIUM): Cookie domain validation bypass - **CVE-2025-14017** (MEDIUM): Protocol downgrade vulnerability - **CVE-2025-15224** (LOW): Information disclosure in verbose logging **Why Acceptable**: - curl only used for **internal healthcheck scripts** (localhost:8080) - All URLs are **hardcoded** - no user-controllable input - Healthchecks use simple HTTP GET to `http://127.0.0.1:8080/api/v1/health` - No cookies, no TLS, no external connections, no verbose logging - Container network isolated from external threats - Application uses Go's HTTP client for all real work (not curl) --- ## Risk Assessment ### Exploitability: LOW - All vulnerabilities require conditions that don't exist in Charon deployment - No attack surface exposed through application interface - Container isolation limits exploitation possibilities ### Impact: LOW - busybox: No shell access available to attackers - curl: Only internal healthchecks affected (non-critical) - Application functionality completely unaffected - Container restart resolves any potential issues ### Overall Risk: LOW Multiple layers of defense-in-depth mitigation make exploitation highly improbable in Charon's deployment architecture. --- ## Mitigation Strategies ### Container Security - **Non-root execution**: Container runs as `caddy:caddy` user - **Capability dropping**: Minimal Linux capabilities (`CAP_NET_BIND_SERVICE` only) - **Read-only filesystem**: Application binaries mounted read-only where possible - **Network isolation**: Container network segmented from host and external networks ### Application Design - **No shell access**: Application provides no command execution interfaces - **Hardcoded URLs**: All curl invocations use string literals (no variables) - **Input validation**: No user input accepted for system commands - **Go HTTP client**: Application uses Go standard library for all external connections ### Monitoring & Remediation - **Daily monitoring**: Alpine Security Team advisories checked daily - **Automated updates**: Renovate Bot creates PRs when patches available - **CI/CD scanning**: Trivy scans on every commit and weekly full scans - **Fast remediation**: < 24 hours to rebuild and deploy after upstream patch --- ## Why No Patches Yet? **Alpine Security Team has not released patches** for these CVEs as of 2026-01-13: - busybox 1.37.0-r21+ (with CVE-2025-60876 fix): Not available - curl 8.14.2+ (with fixes for 7 CVEs): Not available This is a **wait-for-upstream situation**, not a negligence issue. Alpine is actively working on patches. --- ## Acceptance Decision **Decision**: ACCEPT all 9 vulnerabilities pending upstream Alpine patches **Approved By**: Security Team & Engineering Director **Date**: 2026-01-13 **Next Review**: 2026-02-13 (30 days) **Rationale**: 1. ✅ No application-level vulnerabilities found 2. ✅ No upstream patches available from Alpine 3. ✅ Low exploitability in containerized deployment 4. ✅ Multiple layers of effective mitigation 5. ✅ Active monitoring and fast remediation process 6. ✅ Consistent with industry best practices for vulnerability management --- ## Documentation Comprehensive vulnerability acceptance documentation created: - **[VULNERABILITY_ACCEPTANCE.md](../security/VULNERABILITY_ACCEPTANCE.md)**: Complete risk assessment for all 9 CVEs - Detailed exploitability and impact analysis for each CVE - Specific mitigation strategies per vulnerability - Monitoring and remediation plans - Compliance and audit trail - **[SECURITY.md](../../SECURITY.md)**: Updated with Alpine CVE summary and reference --- ## Transparency & Compliance This acceptance follows industry-standard vulnerability management practices: - **NIST SP 800-53**: RA-3 (Risk Assessment), RA-5 (Vulnerability Scanning) - **ISO 27001**: A.12.6.1 (Management of technical vulnerabilities) - **CIS Controls**: Control 7 (Continuous Vulnerability Management) - **OWASP**: Risk-based vulnerability prioritization All decisions, risk assessments, and mitigation strategies are documented and auditable. --- ## Continuous Monitoring ### Automated - GitHub Dependabot: Package update monitoring - Renovate Bot: Automated PR creation for updates - Trivy: Weekly security scans (Sunday 02:00 UTC) - Supply Chain Verification: Every PR and release ### Manual - Daily: Alpine Security advisories during active periods - Weekly: Security team reviews Alpine feed - Monthly: Comprehensive accepted risk review - Quarterly: Full mitigation strategy evaluation ### Escalation Criteria Immediate remediation if: - Severity upgraded to HIGH or CRITICAL - Active exploitation detected in the wild - CISA KEV listing - Public proof-of-concept exploit - Regulatory/compliance requirement --- ## Next Steps 1. ✅ Vulnerability acceptance documented 2. ✅ Security policy updated 3. ⏳ Monitor Alpine Security Team for patches 4. ⏳ Automated remediation when patches available (< 24 hours) 5. ⏳ Review date: 2026-02-13 (30 days) --- ## Questions? For questions about this vulnerability acceptance decision, please refer to: - **Full Risk Assessment**: [VULNERABILITY_ACCEPTANCE.md](../security/VULNERABILITY_ACCEPTANCE.md) - **Security Policy**: [SECURITY.md](../../SECURITY.md) - **PR Remediation Plan**: [current_spec.md](../plans/current_spec.md) Or reach out to the security team via GitHub Security Advisories or project discussions. --- **Prepared By**: Security Team & Engineering **Date**: 2026-01-13 **PR**: #461 - DNS Challenge Support