attack-tree.md

Attack Tree Analysis for smallstep/certificates

Objective: Attacker's Goal: To compromise an application that uses smallstep/certificates by exploiting weaknesses or vulnerabilities related to certificate management, leading to unauthorized access or control.

Attack Tree Visualization

Compromise Application via Certificate Exploitation ├───[AND]─ [HIGH-RISK PATH] Compromise Certificate Infrastructure [CRITICAL NODE] │ ├───[OR]─ [HIGH-RISK PATH] Compromise CA Private Key [CRITICAL NODE] │ │ ├─── [HIGH-RISK PATH] File System Access on CA Server [CRITICAL NODE] │ │ │ ├─── [HIGH-RISK PATH] Weak File Permissions [CRITICAL NODE] │ │ ├─── [HIGH-RISK PATH] Insider Threat [CRITICAL NODE] │ │ ├─── [HIGH-RISK PATH] Backup/Storage Compromise [CRITICAL NODE] │ │ │ ├─── [HIGH-RISK PATH] Insecure Backups [CRITICAL NODE] │ │ ├─── [HIGH-RISK PATH] Exploit Software Vulnerabilities in step-ca [CRITICAL NODE] │ │ │ ├─── [HIGH-RISK PATH] Known Vulnerabilities [CRITICAL NODE] │ │ │ ├─── [HIGH-RISK PATH] API Vulnerabilities [CRITICAL NODE] │ │ │ │ ├─── [HIGH-RISK PATH] Authentication/Authorization Bypass [CRITICAL NODE] │ │ ├─── [HIGH-RISK PATH] Social Engineering/Phishing CA Admins [CRITICAL NODE] │ ├───[OR]─ Compromise Issued Certificates │ │ ├─── Certificate Theft │ │ │ ├─── [HIGH-RISK PATH] Endpoint Compromise (Server/Client) │ │ │ │ ├─── [HIGH-RISK PATH] Malware Infection │ │ │ │ ├─── [HIGH-RISK PATH] Weak Access Controls on Certificate Storage [CRITICAL NODE] │ │ │ └─── [HIGH-RISK PATH] Weak Certificate Generation/Storage by Application │ │ │ ├─── [HIGH-RISK PATH] Insecure Storage of Certificates/Keys [CRITICAL NODE] │ ├───[OR]─ [HIGH-RISK PATH] Exploit Certificate Validation Weaknesses in Application [CRITICAL NODE] │ │ ├─── [HIGH-RISK PATH] Bypass Certificate Validation [CRITICAL NODE] │ │ │ ├─── [HIGH-RISK PATH] Configuration Errors [CRITICAL NODE] │ │ │ │ ├─── [HIGH-RISK PATH] Disabled Certificate Validation [CRITICAL NODE] │ │ │ │ ├─── [HIGH-RISK PATH] Permissive Validation Settings [CRITICAL NODE] │ │ │ │ ├─── [HIGH-RISK PATH] Code Logic Errors [CRITICAL NODE] │ │ │ ├─── [HIGH-RISK PATH] Man-in-the-Middle (MitM) Attacks (Exploiting Validation Gaps) [CRITICAL NODE] │ │ │ │ ├─── [HIGH-RISK PATH] Lack of Certificate Pinning [CRITICAL NODE] ├───[AND]─ Exploit Compromise for Application Access/Control

Attack Tree Path: 1. [HIGH-RISK PATH] Compromise CA Private Key [CRITICAL NODE]

• Attack Vectors:
  • [HIGH-RISK PATH] File System Access on CA Server [CRITICAL NODE]:
    • [HIGH-RISK PATH] Weak File Permissions [CRITICAL NODE]: Attacker exploits incorrectly configured file permissions on the CA server to directly access and steal the CA private key file.
  • [HIGH-RISK PATH] Insider Threat [CRITICAL NODE]: A malicious insider with legitimate access to the CA server abuses their privileges to steal the CA private key.
  • [HIGH-RISK PATH] Backup/Storage Compromise [CRITICAL NODE]:
    • [HIGH-RISK PATH] Insecure Backups [CRITICAL NODE]: Attacker gains access to insecurely stored backups of the CA private key, which are not properly encrypted or access-controlled.
  • [HIGH-RISK PATH] Exploit Software Vulnerabilities in step-ca [CRITICAL NODE]:
    • [HIGH-RISK PATH] Known Vulnerabilities [CRITICAL NODE]: Attacker exploits publicly known vulnerabilities in specific versions of the step-ca software to gain unauthorized access and potentially extract the CA private key.
    • [HIGH-RISK PATH] API Vulnerabilities [CRITICAL NODE]:
      • [HIGH-RISK PATH] Authentication/Authorization Bypass [CRITICAL NODE]: Attacker bypasses authentication or authorization mechanisms in the step-ca API to access key management functions and potentially retrieve the CA private key.
  • [HIGH-RISK PATH] Social Engineering/Phishing CA Admins [CRITICAL NODE]: Attacker uses social engineering or phishing techniques to trick CA administrators into revealing credentials or performing actions that directly compromise the CA private key.

Attack Tree Path: 2. [HIGH-RISK PATH] Endpoint Compromise (Server/Client)

• Attack Vectors:
  • [HIGH-RISK PATH] Malware Infection: Malware on a server or client system steals private keys associated with issued certificates.

Attack Tree Path: 3. [HIGH-RISK PATH] Weak Access Controls on Certificate Storage [CRITICAL NODE]

• Attack Vectors:
  • Certificates and their private keys are stored on servers or clients with weak file permissions or access controls, allowing unauthorized users or processes to access and steal them.

Attack Tree Path: 4. [HIGH-RISK PATH] Weak Certificate Generation/Storage by Application

• Attack Vectors:
  • [HIGH-RISK PATH] Insecure Storage of Certificates/Keys [CRITICAL NODE]: The application itself stores issued certificates and their private keys insecurely, such as in plaintext in databases, logs, or easily accessible files.

Attack Tree Path: 5. [HIGH-RISK PATH] Exploit Certificate Validation Weaknesses in Application [CRITICAL NODE]

• Attack Vectors:
  • [HIGH-RISK PATH] Bypass Certificate Validation [CRITICAL NODE]:
    • [HIGH-RISK PATH] Configuration Errors [CRITICAL NODE]:
      • [HIGH-RISK PATH] Disabled Certificate Validation [CRITICAL NODE]: Application is misconfigured to completely disable certificate validation, allowing any certificate (even invalid or rogue ones) to be accepted.
      • [HIGH-RISK PATH] Permissive Validation Settings [CRITICAL NODE]: Application is configured with overly permissive validation settings, such as ignoring certificate errors or not performing proper chain verification.
    • [HIGH-RISK PATH] Code Logic Errors [CRITICAL NODE]: Bugs in the application's code lead to incorrect or bypassed certificate validation logic, allowing invalid or rogue certificates to be accepted.
  • [HIGH-RISK PATH] Man-in-the-Middle (MitM) Attacks (Exploiting Validation Gaps) [CRITICAL NODE]:
    • [HIGH-RISK PATH] Lack of Certificate Pinning [CRITICAL NODE]: Application does not implement certificate pinning, making it vulnerable to MitM attacks where an attacker can present a rogue certificate and bypass validation.