kqlMITfrom Azure/Azure-Sentinel
User account added to built in domain local or global group
'Identifies when a user account has been added to a privileged built in domain local group or global group such as the Enterprise Admins, Cert Publishers or DnsAdmins. Be sure to verify this is an expected addition.'
Quality
92
FP risk
—
Forks
0
Views
0
Rule sourceDetections/SecurityEvent/UserAccountAddedToPrivlegeGroup_1h.yaml
// For AD SID mappings - https://docs.microsoft.com/windows/security/identity-protection/access-control/active-directory-security-groups
let WellKnownLocalSID = "S-1-5-32-5[0-9][0-9]$";
let WellKnownGroupSID = "S-1-5-21-[0-9]*-[0-9]*-[0-9]*-5[0-9][0-9]$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1102$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1103$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-498$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1000$";
union isfuzzy=true
(
SecurityEvent
// 4728 - A member was added to a security-enabled global group
// 4732 - A member was added to a security-enabled local group
// 4756 - A member was added to a security-enabled universal group
| where EventID in (4728, 4732, 4756)
| where AccountType == "User"
| where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID
// Exclude Remote Desktop Users group: S-1-5-32-555
| where TargetSid !in ("S-1-5-32-555")
| extend SimpleMemberName = iff(MemberName == "-", MemberName, substring(MemberName, 3, indexof_regex(MemberName, @",OU|,CN") - 3))
| project TimeGenerated, EventID, Activity, Computer, SimpleMemberName, MemberName, MemberSid, TargetAccount, TargetUserName, TargetDomainName, TargetSid, UserPrincipalName,
SubjectAccount, SubjectUserName, SubjectDomainName, SubjectUserSid
),
(
WindowsEvent
// 4728 - A member was added to a security-enabled global group
// 4732 - A member was added to a security-enabled local group
// 4756 - A member was added to a security-enabled universal group
| where EventID in (4728, 4732, 4756) and not(EventData has "S-1-5-32-555")
| extend SubjectUserSid = tostring(EventData.SubjectUserSid)
| extend Account = strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
| extend AccountType=case(Account endswith "$" or SubjectUserSid in ("S-1-5-18", "S-1-5-19", "S-1-5-20"), "Machine", isempty(SubjectUserSid), "", "User")
| extend MemberName = tostring(EventData.MemberName)
| where AccountType == "User"
| extend TargetSid = tostring(EventData.TargetSid)
| where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID
// Exclude Remote Desktop Users group: S-1-5-32-555
| where TargetSid !in ("S-1-5-32-555")
| extend SimpleMemberName = iff(MemberName == "-", MemberName, substring(MemberName, 3, indexof_regex(MemberName, @",OU|,CN") - 3))
| extend MemberSid = tostring(EventData.MemberSid)
| extend TargetUserName = tostring(EventData.TargetUserName), TargetDomainName = tostring(EventData.TargetDomainName),
TargetAccount = strcat(tostring(EventData.TargetDomainName),"\\", tostring(EventData.TargetUserName))
| extend UserPrincipalName = tostring(EventData.UserPrincipalName)
| extend SubjectUserName = tostring(EventData.SubjectUserName), SubjectDomainName = tostring(EventData.SubjectDomainName),
SubjectAccount = strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
| project TimeGenerated, EventID, Computer, SimpleMemberName, MemberName, MemberSid, TargetAccount, TargetUserName, TargetDomainName, TargetSid, UserPrincipalName,
SubjectAccount, SubjectUserName, SubjectDomainName, SubjectUserSid
)
| extend GroupAddedMemberTo = TargetAccount, AddedByAccount = SubjectAccount, AddedByAccountName = SubjectUserName, AddedByAccountDomainName = SubjectDomainName,
AddedByAccountSid = SubjectUserSid, AddedMemberName = SimpleMemberName, AddedMemberSid = MemberSid
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
| project-away DomainIndex