Privilege Escalation

Privilege Escalation

In the privilege escalation phase, attackers elevate their permissions within a compromised system, gaining higher-level access that allows them to control more resources and execute more damaging actions. Privilege escalation (often shortened to PrivEsc) is essential for attackers to bypass access restrictions, reach sensitive data, or maintain control over a network. Some privilege escalation methods overlap with persistence techniques, as attackers can use them to ensure long-term access at higher privilege levels.

Here are some common privilege escalation techniques, including Sudo exploits, token/key theft, IAM/group policy modifications, and the use of persistence exploits as PrivEsc methods.

1. Sudo Exploits

• Definition: On Unix-based systems, sudo allows users to execute commands with elevated privileges (typically as the root user). Attackers may attempt to exploit misconfigurations in sudo or vulnerabilities to gain root access.
• Common Sudo Exploits:
  • Misconfigured Sudoers File: Sometimes, the sudoers file (which controls sudo permissions) grants more privileges than necessary. Attackers can exploit such configurations to execute commands as root.
  • Unrestricted Sudo Permissions: In cases where users are allowed to execute all commands via sudo without restrictions, attackers can quickly escalate their privileges.
• Security Implications: If attackers can exploit sudo, they gain root privileges, allowing them to modify critical system files, install software, and control almost every aspect of the system.

2. Token/Key Theft

• Definition: Many operating systems and cloud environments use tokens, keys, and credentials to authenticate and authorize users and processes. Attackers may steal these tokens or keys to gain elevated privileges.
• Methods of Token/Key Theft:
  • Access Tokens (Windows): Attackers can steal tokens that represent user sessions, impersonating users with higher privileges.
  • Cloud Access Keys: In cloud environments (e.g., AWS, Azure), attackers may attempt to steal access keys or tokens tied to privileged accounts to control cloud resources.
  • Session Cookies: Attackers may steal session cookies from web browsers or applications to impersonate users without needing their passwords.
• Security Implications: Stolen tokens and keys grant attackers higher access without requiring further exploitation, allowing them to bypass access controls, manipulate data, and control resources directly.

3. IAM/Group Policy Modifications

• Definition: In enterprise and cloud environments, Identity and Access Management (IAM) systems and group policies control user permissions and access rights. Attackers may modify IAM policies or group memberships to escalate their privileges.
• Techniques:
  • IAM Policy Modification: Attackers with sufficient access may modify IAM policies to grant themselves broader permissions, such as administrator rights in cloud environments.
  • Adding to Privileged Groups: Attackers with local admin rights on Windows, for example, can add their account to higher-privilege groups (e.g., Domain Admins or Local Administrators).
• Security Implications: By altering IAM policies or group memberships, attackers gain access to additional resources or permissions, making it easier for them to control the environment and access sensitive data.

4. Persistence Exploits as Privilege Escalation Methods

• Definition: Many persistence techniques double as privilege escalation methods, as they help attackers gain or retain higher privileges.
• Examples:
  • Scheduled Tasks: If attackers create scheduled tasks under system or administrator accounts, they gain elevated access upon task execution.
  • DLL Side-Loading: Attackers can plant malicious DLLs in directories used by privileged applications. When the application loads the DLL, it runs with elevated privileges, effectively escalating the attacker’s access.
  • WMI Persistence: Attackers who use WMI scripts for persistence can configure them to execute with system-level privileges, providing elevated access.
• Security Implications: By using persistence techniques that allow elevated permissions, attackers not only gain continued access but also ensure they can operate with high-level privileges, increasing the potential damage they can cause.

Summary

• Sudo Exploits target privilege misconfigurations in Unix-based systems to gain root access.
• Token/Key Theft involves stealing access tokens, session cookies, or cloud keys, allowing attackers to impersonate privileged users.
• IAM/Group Policy Modifications enable attackers to expand their permissions by altering user roles and group memberships.
• Persistence Exploits as PrivEsc Methods use scheduled tasks, DLL side-loading, and WMI to establish persistent elevated access, often doubling as privilege escalation.

These privilege escalation methods are critical in allowing attackers to deepen their control over a compromised environment, enabling them to perform more sophisticated actions and access sensitive resources. Regular auditing of user privileges, monitoring group memberships, and securing token storage are effective ways to mitigate these threats.