Modify Authentication Process: Подключаемые модули аутентификации
Other sub-techniques of Modify Authentication Process (9)
Adversaries may modify pluggable authentication modules (PAM) to access user credentials or enable otherwise unwarranted access to accounts. PAM is a modular system of configuration files, libraries, and executable files which guide authentication for many services. The most common authentication module is pam_unix.so
, which retrieves, sets, and verifies account authentication information in /etc/passwd
and /etc/shadow
.(Citation: Apple PAM)(Citation: Man Pam_Unix)(Citation: Red Hat PAM)
Adversaries may modify components of the PAM system to create backdoors. PAM components, such as pam_unix.so
, can be patched to accept arbitrary adversary supplied values as legitimate credentials.(Citation: PAM Backdoor)
Malicious modifications to the PAM system may also be abused to steal credentials. Adversaries may infect PAM resources with code to harvest user credentials, since the values exchanged with PAM components may be plain-text since PAM does not store passwords.(Citation: PAM Creds)(Citation: Apple PAM)
Примеры процедур |
|
Название | Описание |
---|---|
Ebury |
Ebury can deactivate PAM modules to tamper with the sshd configuration.(Citation: ESET Ebury Oct 2017) |
Skidmap |
Skidmap has the ability to replace the pam_unix.so file on an infected machine with its own malicious version that accepts a specific backdoor password for all users.(Citation: Trend Micro Skidmap) |
Контрмеры |
|
Контрмера | Описание |
---|---|
Multi-factor Authentication |
Multi-Factor Authentication (MFA) enhances security by requiring users to provide at least two forms of verification to prove their identity before granting access. These factors typically include: - *Something you know*: Passwords, PINs. - *Something you have*: Physical tokens, smartphone authenticator apps. - *Something you are*: Biometric data such as fingerprints, facial recognition, or retinal scans. Implementing MFA across all critical systems and services ensures robust protection against account takeover and unauthorized access. This mitigation can be implemented through the following measures: Identity and Access Management (IAM): - Use IAM solutions like Azure Active Directory, Okta, or AWS IAM to enforce MFA policies for all user logins, especially for privileged roles. - Enable conditional access policies to enforce MFA for risky sign-ins (e.g., unfamiliar devices, geolocations). Authentication Tools and Methods: - Use authenticator applications such as Google Authenticator, Microsoft Authenticator, or Authy for time-based one-time passwords (TOTP). - Deploy hardware-based tokens like YubiKey, RSA SecurID, or smart cards for additional security. - Enforce biometric authentication for compatible devices and applications. Secure Legacy Systems: - Integrate MFA solutions with older systems using third-party tools like Duo Security or Thales SafeNet. - Enable RADIUS/NPS servers to facilitate MFA for VPNs, RDP, and other network logins. Monitoring and Alerting: - Use SIEM tools to monitor failed MFA attempts, login anomalies, or brute-force attempts against MFA systems. - Implement alerts for suspicious MFA activities, such as repeated failed codes or new device registrations. Training and Policy Enforcement: - Educate employees on the importance of MFA and secure authenticator usage. - Enforce policies that require MFA on all critical systems, especially for remote access, privileged accounts, and cloud applications. |
Privileged Account Management |
Privileged Account Management focuses on implementing policies, controls, and tools to securely manage privileged accounts (e.g., SYSTEM, root, or administrative accounts). This includes restricting access, limiting the scope of permissions, monitoring privileged account usage, and ensuring accountability through logging and auditing.This mitigation can be implemented through the following measures: Account Permissions and Roles: - Implement RBAC and least privilege principles to allocate permissions securely. - Use tools like Active Directory Group Policies to enforce access restrictions. Credential Security: - Deploy password vaulting tools like CyberArk, HashiCorp Vault, or KeePass for secure storage and rotation of credentials. - Enforce password policies for complexity, uniqueness, and expiration using tools like Microsoft Group Policy Objects (GPO). Multi-Factor Authentication (MFA): - Enforce MFA for all privileged accounts using Duo Security, Okta, or Microsoft Azure AD MFA. Privileged Access Management (PAM): - Use PAM solutions like CyberArk, BeyondTrust, or Thycotic to manage, monitor, and audit privileged access. Auditing and Monitoring: - Integrate activity monitoring into your SIEM (e.g., Splunk or QRadar) to detect and alert on anomalous privileged account usage. Just-In-Time Access: - Deploy JIT solutions like Azure Privileged Identity Management (PIM) or configure ephemeral roles in AWS and GCP to grant time-limited elevated permissions. *Tools for Implementation* Privileged Access Management (PAM): - CyberArk, BeyondTrust, Thycotic, HashiCorp Vault. Credential Management: - Microsoft LAPS (Local Admin Password Solution), Password Safe, HashiCorp Vault, KeePass. Multi-Factor Authentication: - Duo Security, Okta, Microsoft Azure MFA, Google Authenticator. Linux Privilege Management: - sudo configuration, SELinux, AppArmor. Just-In-Time Access: - Azure Privileged Identity Management (PIM), AWS IAM Roles with session constraints, GCP Identity-Aware Proxy. |
Обнаружение
Monitor PAM configuration and module paths (ex: /etc/pam.d/
) for changes. Use system-integrity tools such as AIDE and monitoring tools such as auditd to monitor PAM files.
Look for suspicious account behavior across systems that share accounts, either user, admin, or service accounts. Examples: one account logged into multiple systems simultaneously; multiple accounts logged into the same machine simultaneously; accounts logged in at odd times (ex: when the user is not present) or outside of business hours. Activity may be from interactive login sessions or process ownership from accounts being used to execute binaries on a remote system as a particular account. Correlate other security systems with login information (e.g., a user has an active login session but has not entered the building or does not have VPN access).
Ссылки
- zephrax. (2018, August 3). linux-pam-backdoor. Retrieved June 25, 2020.
- Red Hat. (n.d.). CHAPTER 2. USING PLUGGABLE AUTHENTICATION MODULES (PAM). Retrieved June 25, 2020.
- Fernández, J. M. (2018, June 27). Exfiltrating credentials via PAM backdoors & DNS requests. Retrieved November 17, 2024.
- die.net. (n.d.). pam_unix(8) - Linux man page. Retrieved June 25, 2020.
- Apple. (2011, May 11). PAM - Pluggable Authentication Modules. Retrieved June 25, 2020.
- Vachon, F. (2017, October 30). Windigo Still not Windigone: An Ebury Update . Retrieved February 10, 2021.
- Remillano, A., Urbanec, J. (2019, September 19). Skidmap Linux Malware Uses Rootkit Capabilities to Hide Cryptocurrency-Mining Payload. Retrieved June 4, 2020.
Связанные риски
Каталоги
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