Delegated Managed Service Account Modification by an Unusual User

Author: Elastic
Source: upstream

Detects modifications in the msDS-ManagedAccountPrecededByLink attribute of a delegated managed service account by an unusual subject account. Attackers can abuse this attribute to take over the permission of a target account and inherit it's permissions allowing them to further elevate privileges.

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	`T1078` Valid Accounts, `T1078.002` Valid Accounts: Domain Accounts
Persistence	`T1078` Valid Accounts, `T1078.002` Valid Accounts: Domain Accounts, `T1098` Account Manipulation
Privilege Escalation	`T1078` Valid Accounts, `T1078.002` Valid Accounts: Domain Accounts, `T1098` Account Manipulation
Defense Evasion	`T1078` Valid Accounts, `T1078.002` Valid Accounts: Domain Accounts

Event coverage

Provider	Event ID	Title
Security-Auditing	5136	A directory service object was modified.

Stages and Predicates

Stage 1: `kql:new_terms`

winlog.event_data.AttributeLDAPDisplayName:"msDS-ManagedAccountPrecededByLink"

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.