Detect Account Manipulation in Splunk
Adversaries may manipulate accounts to maintain and/or elevate access to victim systems. Account manipulation may consist of any action that preserves or modifies adversary access to a compromised account, such as modifying credentials or permission groups. These actions could also include account activity designed to subvert security policies, such as performing iterative password updates to bypass password duration policies and preserve the life of compromised credentials. In order to create or manipulate accounts, the adversary must already have sufficient permissions on systems or the domain. Account manipulation may also lead to privilege escalation where modifications grant access to additional roles, permissions, or higher-privileged Valid Accounts.
MITRE ATT&CK
- Tactic
- Persistence Privilege Escalation
- Technique
- T1098 Account Manipulation
- Canonical reference
- https://attack.mitre.org/techniques/T1098/
SPL Detection Query
index=wineventlog sourcetype="WinEventLog:Security" (EventCode=4738 OR EventCode=4670 OR EventCode=4732 OR EventCode=4728 OR EventCode=4756 OR EventCode=4735 OR EventCode=4648)
| eval ChangeType=case(
EventCode=4738, "UserAccountModified",
EventCode=4670, "PermissionsChanged",
EventCode=4732, "AddedToLocalGroup",
EventCode=4728, "AddedToGlobalGroup",
EventCode=4756, "AddedToUniversalGroup",
EventCode=4735, "LocalGroupModified",
EventCode=4648, "ExplicitCredentialLogon",
"Unknown"
)
| eval SensitiveGroup=if(match(lower(coalesce(TargetUserName, Group_Name, "")), "domain admins|enterprise admins|schema admins|administrators|account operators|backup operators|server operators|group policy creator owners|remote management users|esx admins"), 1, 0)
| eval IsHighRisk=if(SensitiveGroup=1 OR EventCode=4670, 1, 0)
| eval ActorAccount=coalesce(SubjectUserName, Subject_Account_Name, "Unknown")
| eval TargetAccount=coalesce(TargetUserName, Target_Account_Name, MemberName, "Unknown")
| eval TargetDomain=coalesce(TargetDomainName, "Unknown")
| where NOT (ActorAccount="-" OR ActorAccount="SYSTEM" OR ActorAccount="LOCAL SERVICE" OR ActorAccount="NETWORK SERVICE")
| stats count as TotalEvents,
sum(IsHighRisk) as HighRiskCount,
values(ChangeType) as ChangeTypes,
values(TargetAccount) as AffectedAccounts,
earliest(_time) as FirstSeen,
latest(_time) as LastSeen
by ActorAccount, host
| eval RiskScore=case(
HighRiskCount >= 3, "Critical",
HighRiskCount >= 1, "High",
TotalEvents >= 10, "Medium",
"Low"
)
| where TotalEvents >= 1
| sort - HighRiskCount, - TotalEventsDetects account manipulation activity using Windows Security event logs. Monitors for user account changes (4738), permission modifications (4670), group membership additions to local/global/universal groups (4732/4728/4756), local group changes (4735), and explicit credential logon events (4648). Flags activity targeting sensitive privileged groups and assigns a risk score based on high-risk event counts. Filters out SYSTEM and service account actors to reduce noise from OS-generated events.
Data Sources
Required Sourcetypes
False Positives & Tuning
- IT administrators performing legitimate account provisioning or group membership changes during onboarding or role transitions
- Automated identity management systems (SailPoint, Saviynt, AD Connect) performing scheduled sync operations that generate bulk account modification events
- Help desk staff performing password resets or account unlock operations which generate 4738 events
- Group Policy or SCCM deployments that modify local group membership across endpoints as part of standard configuration management
- Scheduled account maintenance scripts that iterate through stale accounts and modify their properties
Other platforms for T1098
Testing Methodology
Validate this detection against 5 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Add User to Local Administrators Group
Expected signal: Security Event ID 4732: A member was added to a security-enabled local group. SubjectUserName = actor, TargetUserName = Administrators (group), MemberName = df00tech-testuser. Sysmon Event ID 1 if executed via cmd.exe: Process Create with Image=net.exe, CommandLine='net localgroup Administrators df00tech-testuser /add'.
- Test 2Modify User Account Password — Simulate Credential Manipulation
Expected signal: Security Event ID 4738: A user account was changed. SubjectUserName = executing account, TargetUserName = df00tech-testuser. The 'Changed Attributes' section will show 'Password Last Set' updated. Sysmon Event ID 1: Process Create with net.exe command line visible.
- Test 3Disable Password Expiry on Account (UserAccountControl Manipulation)
Expected signal: Security Event ID 4738: A user account was changed. The event detail will show UserAccountControl change with the new value including the DONT_EXPIRE_PASSWORD flag (0x10000 bit set). SubjectUserName identifies the actor performing the change.
- Test 4Rename Administrator Account (Lazarus Group TTPs)
Expected signal: Security Event ID 4738: A user account was changed. TargetUserName will show the new account name, and 'SAM Account Name' in the changed attributes will reflect the rename. Sysmon Event ID 1: Process Create with wmic.exe and the rename command visible in CommandLine.
- Test 5Grant Remote Desktop Access via Group Membership
Expected signal: Security Event ID 4732: A member was added to a security-enabled local group. TargetUserName = Remote Desktop Users, MemberName = df00tech-testuser, SubjectUserName = executing account. Sysmon Event ID 1: Process Create for powershell.exe with Add-LocalGroupMember in CommandLine.
References (10)
- https://attack.mitre.org/techniques/T1098/
- https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventID=4738
- https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventID=4670
- https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventID=4732
- https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/event-4738
- https://blog.stealthbits.com/manipulating-user-passwords-with-mimikatz-SetNTLM-ChangeNTLM
- https://github.com/gentilkiwi/mimikatz/issues/92
- https://www.fireeye.com/blog/threat-research/2021/06/darkside-affiliate-supply-chain-software-compromise.html
- https://www.volexity.com/blog/2021/03/01/the-mass-exploitation-of-on-premises-exchange-servers/
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1098/T1098.md
Unlock Pro Content
Get the full detection package for T1098 including response playbook, investigation guide, and atomic red team tests.