Remote Services: SSH
Adversaries may use Valid Accounts to log into remote machines using Secure Shell (SSH). The adversary may then perform actions as the logged-on user.
SSH is a protocol that allows authorized users to open remote shells on other computers. Many Linux and macOS versions come with SSH installed by default, although typically disabled until the user enables it. The SSH server can be configured to use standard password authentication or public-private keypairs in lieu of or in addition to a password. In this authentication scenario, the user’s public key must be in a special file on the computer running the server that lists which keypairs are allowed to login as that user.
|M1042||Disable or Remove Feature or Program||
Disable the SSH daemon on systems that do not require it.
Require multi-factor authentication for SSH connections wherever possible.
|M1018||User Account Management||
Limit which user accounts are allowed to login via SSH.
Use of SSH may be legitimate depending on the environment and how it’s 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.
- SSH.COM. (n.d.). SSH (Secure Shell). Retrieved March 23, 2020.
- Hawley et al. (2019, January 29). APT39: An Iranian Cyber Espionage Group Focused on Personal Information. Retrieved February 19, 2019.
- Cobalt Strike. (2017, December 8). Tactics, Techniques, and Procedures. Retrieved December 20, 2017.
- Schroeder, W., Warner, J., Nelson, M. (n.d.). Github PowerShellEmpire. Retrieved April 28, 2016.
- CISA. (2020, September 15). Iran-Based Threat Actor Exploits VPN Vulnerabilities. Retrieved December 21, 2020.
- Kaspersky Lab's Global Research & Analysis Team. (2016, February 8). APT-style bank robberies increase with Metel, GCMAN and Carbanak 2.0 attacks. Retrieved April 20, 2016.
- Singer, G. (2020, April 3). Threat Alert: Kinsing Malware Attacks Targeting Container Environments. Retrieved April 1, 2021.
- Plan, F., et all. (2019, March 4). APT40: Examining a China-Nexus Espionage Actor. Retrieved March 18, 2019.
- PwC and BAE Systems. (2017, April). Operation Cloud Hopper. Retrieved April 5, 2017.
- Unit 42. (2017, December 15). Unit 42 Playbook Viewer. Retrieved December 20, 2017.
- Anomali Labs. (2019, March 15). Rocke Evolves Its Arsenal With a New Malware Family Written in Golang. Retrieved April 24, 2019.
- Miller, S, et al. (2019, April 10). TRITON Actor TTP Profile, Custom Attack Tools, Detections, and ATT&CK Mapping. Retrieved April 16, 2019.