Objective: To issue fraudulent TLS certificates for domains the attacker does not control, or to disrupt the availability of the certificate authority (CA) service.
- Attacker's Goal: Issue Fraudulent Certificates OR Disrupt CA Service Availability (Likelihood: Medium, Impact: Critical, Effort: High, Skill: Advanced, Detection: Moderate)
- Compromise of CA Private Key (Likelihood: Low, Impact: Critical, Effort: Very High, Skill: Expert, Detection: Hard)
- Physical Access to HSM (Likelihood: Very Low, Impact: Critical, Effort: Very High, Skill: Expert, Detection: Very Hard)
- Software Vulnerability in HSM (Likelihood: Very Low, Impact: Critical, Effort: Very High, Skill: Expert, Detection: Very Hard)
- Compromise of Key Management System (Likelihood: Low, Impact: Critical, Effort: High, Skill: Advanced, Detection: Hard)
- Exploit Vulnerabilities in Boulder Software (Likelihood: Medium, Impact: High, Effort: Moderate, Skill: Intermediate, Detection: Moderate)
- Injection Vulnerabilities (SQLi, Command Injection) (Likelihood: Medium, Impact: High, Effort: Moderate, Skill: Intermediate, Detection: Moderate)
- Authentication/Authorization Bypass (Likelihood: Low, Impact: High, Effort: High, Skill: Advanced, Detection: Moderate)
- Remote Code Execution (RCE) (Likelihood: Low, Impact: Critical, Effort: High, Skill: Expert, Detection: Moderate)
- Denial of Service (DoS) Vulnerabilities (Likelihood: Medium, Impact: High, Effort: Low, Skill: Intermediate, Detection: Easy)
- Compromise of Supporting Infrastructure (Likelihood: Medium, Impact: High, Effort: Moderate, Skill: Intermediate, Detection: Moderate)
- Database Compromise (e.g., MySQL) (Likelihood: Medium, Impact: High, Effort: Moderate, Skill: Intermediate, Detection: Moderate)
- Compromise of DNS Infrastructure (Likelihood: Low, Impact: High, Effort: High, Skill: Advanced, Detection: Moderate)
- Compromise of Network Infrastructure (Likelihood: Low, Impact: High, Effort: High, Skill: Advanced, Detection: Hard)
- Compromise of CA Private Key (Likelihood: Low, Impact: Critical, Effort: Very High, Skill: Expert, Detection: Hard)
Attack Tree Path: Compromise of CA Private Key
Description: This is the most critical node. If the attacker gains access to the CA's private key, they can issue certificates for any domain, completely undermining the trust model. * Attack Vectors: * Physical Access to HSM: Gaining physical access to the Hardware Security Module (HSM) where the private key is stored. This would likely require bypassing physical security measures. * Likelihood: Very Low (due to physical security). * Impact: Critical (complete compromise). * Effort: Very High (requires physical intrusion, specialized tools). * Skill Level: Expert (physical security, hardware exploitation). * Detection Difficulty: Very Hard (physical intrusion may not be immediately detected). * Software Vulnerability in HSM: Exploiting a vulnerability in the HSM's firmware or software to extract the private key. This is extremely difficult but not impossible. * Likelihood: Very Low (HSMs are designed to be highly secure). * Impact: Critical (complete compromise). * Effort: Very High (requires deep understanding of HSM internals). * Skill Level: Expert (hardware security, vulnerability research). * Detection Difficulty: Very Hard (often requires vendor-specific detection). * Compromise of Key Management System: If the key management system used to handle the CA private key is compromised (e.g., through weak credentials, software vulnerabilities, or insider threat), the attacker could gain access to the key. * Likelihood: Low (assuming reasonable key management practices). * Impact: Critical (complete compromise). * Effort: High (requires compromising a separate, secured system). * Skill Level: Advanced (system administration, potentially exploit development). * Detection Difficulty: Hard (depends on logging and intrusion detection systems).
Attack Tree Path: Exploit Vulnerabilities in Boulder Software
Description: Boulder, like any software, could have vulnerabilities. These could be in the core application logic, dependencies, or interactions with the database. * Attack Vectors: * Injection Vulnerabilities (SQLi, Command Injection): If user-supplied input is not properly sanitized, an attacker could inject malicious code into SQL queries or shell commands. * Likelihood: Medium (common vulnerability type, but Boulder is likely well-tested). * Impact: High (could lead to data exfiltration, code execution). * Effort: Moderate (standard attack techniques, but requires finding a vulnerable input). * Skill Level: Intermediate (knowledge of SQL injection, command injection). * Detection Difficulty: Moderate (web application firewalls and intrusion detection systems can often detect these). * Authentication/Authorization Bypass: Flaws in the authentication or authorization mechanisms could allow an attacker to bypass access controls and gain unauthorized privileges. * Likelihood: Low (core functionality, likely well-tested). * Impact: High (could allow issuing certificates or modifying data). * Effort: High (requires finding a logic flaw in the authentication/authorization flow). * Skill Level: Advanced (deep understanding of authentication protocols and Boulder's implementation). * Detection Difficulty: Moderate (unusual access patterns might be detected). * Remote Code Execution (RCE): A vulnerability that allows an attacker to execute arbitrary code on the server. This is the most severe type of vulnerability. * Likelihood: Low (less common in well-written Go code, but still possible). * Impact: Critical (complete system compromise). * Effort: High (requires finding and exploiting a complex vulnerability). * Skill Level: Expert (vulnerability research, exploit development). * Detection Difficulty: Moderate (unusual system behavior might be detected). * Denial of Service (DoS) Vulnerabilities: Exploiting a vulnerability to make the CA service unavailable. This could involve flooding the server with requests or exploiting a bug that causes the service to crash. * Likelihood: Medium (DoS vulnerabilities can be subtle). * Impact: High (disrupts certificate issuance). * Effort: Low (many tools available for DoS attacks). * Skill Level: Intermediate (understanding of network protocols and DoS techniques). * Detection Difficulty: Easy (performance degradation and service unavailability are obvious).
Attack Tree Path: Compromise of Supporting Infrastructure
Description: Boulder relies on other systems (database, network, etc.). Compromising these systems can indirectly impact Boulder. * Attack Vectors: * Database Compromise (e.g., MySQL): Gaining access to the database could allow an attacker to modify account data, issue certificates, or disrupt service. * Likelihood: Medium (databases are common targets). * Impact: High (data modification, potential certificate issuance). * Effort: Moderate (requires exploiting database vulnerabilities or weak credentials). * Skill Level: Intermediate (database security, SQL injection). * Detection Difficulty: Moderate (database monitoring and intrusion detection). * Compromise of DNS Infrastructure: If an attacker can control the DNS records for the domain being validated, they can potentially redirect validation requests to a server they control. * Likelihood: Low (DNS infrastructure is generally well-protected). * Impact: High (allows for fraudulent certificate issuance). * Effort: High (requires compromising DNS servers or registrars). * Skill Level: Advanced (network security, DNS hijacking techniques). * Detection Difficulty: Moderate (DNS monitoring and anomaly detection). * Compromise of Network Infrastructure: Gaining access to routers, switches, or firewalls could allow an attacker to intercept traffic, modify data, or launch denial-of-service attacks. * Likelihood: Low (network infrastructure is usually well-secured). * Impact: High (can affect all aspects of the system). * Effort: High (requires network penetration skills). * Skill Level: Advanced (network security, penetration testing). * Detection Difficulty: Hard (requires network intrusion detection systems).