Remote Service Session Hijacking: Перехват сессии SSH
Other sub-techniques of Remote Service Session Hijacking (2)
Adversaries may hijack a legitimate user's SSH session to move laterally within an environment. Secure Shell (SSH) is a standard means of remote access on Linux and macOS systems. It allows a user to connect to another system via an encrypted tunnel, commonly authenticating through a password, certificate or the use of an asymmetric encryption key pair. In order to move laterally from a compromised host, adversaries may take advantage of trust relationships established with other systems via public key authentication in active SSH sessions by hijacking an existing connection to another system. This may occur through compromising the SSH agent itself or by having access to the agent's socket. If an adversary is able to obtain root access, then hijacking SSH sessions is likely trivial.(Citation: Slideshare Abusing SSH)(Citation: SSHjack Blackhat)(Citation: Clockwork SSH Agent Hijacking)(Citation: Breach Post-mortem SSH Hijack) SSH Hijacking differs from use of SSH because it hijacks an existing SSH session rather than creating a new session using Valid Accounts.
Контрмеры |
|
| Контрмера | Описание |
|---|---|
| Restrict File and Directory Permissions |
Restrict access by setting directory and file permissions that are not specific to users or privileged accounts. |
| Disable or Remove Feature or Program |
Remove or deny access to unnecessary and potentially vulnerable software to prevent abuse by adversaries. |
| Password Policies |
Set and enforce secure password policies for accounts. |
| Privileged Account Management |
Manage the creation, modification, use, and permissions associated to privileged accounts, including SYSTEM and root. |
Обнаружение
Use of SSH may be legitimate, depending upon the network environment and how it is used. Other factors, such as access patterns and activity that occurs after a remote login, may indicate suspicious or malicious behavior with SSH. Monitor for user accounts logged into systems they would not normally access or access patterns to multiple systems over a relatively short period of time. Also monitor user SSH-agent socket files being used by different users.
Ссылки
- Hodgson, M. (2019, May 8). Post-mortem and remediations for Apr 11 security incident. Retrieved February 17, 2020.
- Beuchler, B. (2012, September 28). SSH Agent Hijacking. Retrieved December 20, 2017.
- Adam Boileau. (2005, August 5). Trust Transience: Post Intrusion SSH Hijacking. Retrieved December 19, 2017.
- Duarte, H., Morrison, B. (2012). (Mis)trusting and (ab)using ssh. Retrieved January 8, 2018.
- Hatch, B. (2004, November 22). SSH and ssh-agent. Retrieved January 8, 2018.
Связанные риски
Каталоги
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