Brute Force: Password Guessing
Other sub-techniques of Brute Force (4)
| ID | Name |
|---|---|
| T1110.001 | Password Guessing |
| T1110.002 | Password Cracking |
| T1110.003 | Password Spraying |
| T1110.004 | Credential Stuffing |
Adversaries with no prior knowledge of legitimate credentials within the system or environment may guess passwords to attempt access to accounts. Without knowledge of the password for an account, an adversary may opt to systematically guess the password using a repetitive or iterative mechanism. An adversary may guess login credentials without prior knowledge of system or environment passwords during an operation by using a list of common passwords. Password guessing may or may not take into account the target's policies on password complexity or use policies that may lock accounts out after a number of failed attempts.
Guessing passwords can be a risky option because it could cause numerous authentication failures and account lockouts, depending on the organization's login failure policies. [1]
Typically, management services over commonly used ports are used when guessing passwords. Commonly targeted services include the following:
- SSH (22/TCP)
- Telnet (23/TCP)
- FTP (21/TCP)
- NetBIOS / SMB / Samba (139/TCP & 445/TCP)
- LDAP (389/TCP)
- Kerberos (88/TCP)
- RDP / Terminal Services (3389/TCP)
- HTTP/HTTP Management Services (80/TCP & 443/TCP)
- MSSQL (1433/TCP)
- Oracle (1521/TCP)
- MySQL (3306/TCP)
- VNC (5900/TCP)
In addition to management services, adversaries may "target single sign-on (SSO) and cloud-based applications utilizing federated authentication protocols," as well as externally facing email applications, such as Office 365.[2]
In default environments, LDAP and Kerberos connection attempts are less likely to trigger events over SMB, which creates Windows "logon failure" event ID 4625.
Procedure Examples
| Name | Description |
|---|---|
| APT28 |
APT28 has used a brute-force/password-spray tooling that operated in two modes: in brute-force mode it typically sent over 300 authentication attempts per hour per targeted account over the course of several hours or days.[3] |
| China Chopper |
China Chopper's server component can perform brute force password guessing against authentication portals.[4] |
| CrackMapExec |
CrackMapExec can brute force passwords for a specified user on a single target system or across an entire network.[5] |
| Emotet |
Emotet has been observed using a hard coded list of passwords to brute force user accounts. [6][7][8][9][10] |
| Pony |
Pony has used a small dictionary of common passwords against a collected list of local accounts.[11] |
| SpeakUp |
SpeakUp can perform brute forcing using a pre-defined list of usernames and passwords in an attempt to log in to administrative panels. [12] |
| Xbash |
Xbash can obtain a list of weak passwords from the C2 server to use for brute forcing as well as attempt to brute force services with open ports.[13][14] |
Mitigations
| Mitigation | Description |
|---|---|
| Account Use Policies |
Set account lockout policies after a certain number of failed login attempts to prevent passwords from being guessed. Too strict a policy may create a denial of service condition and render environments un-usable, with all accounts used in the brute force being locked-out. |
| Multi-factor Authentication |
Use multi-factor authentication. Where possible, also enable multi-factor authentication on externally facing services. |
| Password Policies |
Refer to NIST guidelines when creating password policies. [15] |
Detection
Monitor authentication logs for system and application login failures of Valid Accounts. If authentication failures are high, then there may be a brute force attempt to gain access to a system using legitimate credentials.
References
- Cylance. (2014, December). Operation Cleaver. Retrieved September 14, 2017.
- US-CERT. (2018, March 27). TA18-068A Brute Force Attacks Conducted by Cyber Actors. Retrieved October 2, 2019.
- Microsoft Threat Intelligence Center (MSTIC). (2020, September 10). STRONTIUM: Detecting new patterns in credential harvesting. Retrieved September 11, 2020.
- FireEye. (2018, March 16). Suspected Chinese Cyber Espionage Group (TEMP.Periscope) Targeting U.S. Engineering and Maritime Industries. Retrieved April 11, 2018.
- byt3bl33d3r. (2018, September 8). SMB: Command Reference. Retrieved July 17, 2020.
- Smith, A.. (2017, December 22). Protect your network from Emotet Trojan with Malwarebytes Endpoint Security. Retrieved January 17, 2019.
- Symantec. (2018, July 18). The Evolution of Emotet: From Banking Trojan to Threat Distributor. Retrieved March 25, 2019.
- US-CERT. (2018, July 20). Alert (TA18-201A) Emotet Malware. Retrieved March 25, 2019.
- Mclellan, M.. (2018, November 19). Lazy Passwords Become Rocket Fuel for Emotet SMB Spreader. Retrieved March 25, 2019.
- CIS. (2018, December 12). MS-ISAC Security Primer- Emotet. Retrieved March 25, 2019.
- hasherezade. (2016, April 11). No money, but Pony! From a mail to a trojan horse. Retrieved May 21, 2020.
- Check Point Research. (2019, February 4). SpeakUp: A New Undetected Backdoor Linux Trojan. Retrieved April 17, 2019.
- Xiao, C. (2018, September 17). Xbash Combines Botnet, Ransomware, Coinmining in Worm that Targets Linux and Windows. Retrieved November 14, 2018.
- Trend Micro. (2018, September 19). New Multi-Platform Xbash Packs Obfuscation, Ransomware, Coinminer, Worm and Botnet. Retrieved June 4, 2019.
- Grassi, P., et al. (2017, December 1). SP 800-63-3, Digital Identity Guidelines. Retrieved January 16, 2019.