Adversaries may breach or otherwise leverage organizations who have access to intended victims. Access through trusted third party relationship abuses an existing connection that may not be protected or receives less scrutiny than standard mechanisms of gaining access to a network.
Organizations often grant elevated access to second or third-party external providers in order to allow them to manage internal systems as well as cloud-based environments. Some examples of these relationships include IT services contractors, managed security providers, infrastructure contractors (e.g. HVAC, elevators, physical security). The third-party provider's access may be intended to be limited to the infrastructure being maintained, but may exist on the same network as the rest of the enterprise. As such, Valid Accounts used by the other party for access to internal network systems may be compromised and used.
In Office 365 environments, organizations may grant Microsoft partners or resellers delegated administrator permissions. By compromising a partner or reseller account, an adversary may be able to leverage existing delegated administrator relationships or send new delegated administrator offers to clients in order to gain administrative control over the victim tenant.
During the SolarWinds Compromise, APT29 gained access through compromised accounts at cloud solution partners, and used compromised certificates issued by Mimecast to authenticate to Mimecast customer systems.
Require MFA for all delegated administrator accounts.
Network segmentation can be used to isolate infrastructure components that do not require broad network access.
|M1018||User Account Management||
Properly manage accounts and permissions used by parties in trusted relationships to minimize potential abuse by the party and if the party is compromised by an adversary. In Office 365 environments, partner relationships and roles can be viewed under the "Partner Relationships" page.
|ID||Data Source||Data Component||Detects|
|DS0015||Application Log||Application Log Content||
Configuration management databases (CMDB) and other asset management systems may help with the detection of computer systems or network devices that should not exist on a network. Monitor logs for unexpected actions taken by any delegated administrator accounts.
|DS0028||Logon Session||Logon Session Creation||
Monitor for newly constructed logon behavior that may breach or otherwise leverage organizations who have access to intended victims.
|Logon Session Metadata||
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).
|DS0029||Network Traffic||Network Traffic Content||
Monitor and analyze traffic patterns and packet inspection associated to protocol(s) that do not follow the expected protocol standards and traffic flows (e.g extraneous packets that do not belong to established flows, gratuitous or anomalous traffic patterns, anomalous syntax, or structure) from a trusted entity. Consider correlation with process monitoring and command line to detect anomalous processes execution and command line arguments associated to traffic patterns (e.g. monitor anomalies in use of files that do not normally initiate connections for respective protocol(s)).