Modify Authentication Process T1556

Tactics: Defense Impairment, Persistence, Credential Access

Adversaries may modify authentication mechanisms and processes to access user credentials or enable otherwise unwarranted access to accounts. The authentication process is handled by mechanisms, such as the Local Security Authentication Server (LSASS) process and the Security Accounts Manager (SAM) on Windows, pluggable authentication modules (PAM) on Unix-based systems, and authorization plugins on MacOS systems, responsible for gathering, storing, and validating credentials. By modifying an authentication process, an adversary may be able to authenticate to a service or system without using Valid Accounts.

Events covered

21 catalog events are tagged with this technique by at least one rule.

Authoring guide

These 169 rules share fields, values, and exclusions.

Fields filtered most (161 distinct)

These fields appear most often in rule filters.

FieldRulesHowSample values
EventType32eq 23, in 10exec, modification, ProcessRollup2, User Risk Detection, exec_event
data_stream.dataset27eq 26, in 1okta.system, aws.cloudtrail, azure.auditlogs, azure.identity_protection, azure.signinlogs
sourcetype26eq 26cisco:duo:administrator, cisco:duo:activity, OktaIM2:log, aws:asl, aws:cloudtrail
action20eq 17, contains 2, in 1policy_create, policy_update, disblmfa, UpdateIPRestrictions, UpdateLoginSettings
event.outcome13eq 13success, Success
event.type11eq 11start, change, creation, end
EventID10eq 9, in 124, 4103, 4104, 4688, 4723
process_basename10eq 6, in 5, is_not_null 1, starts_with 1sshd, ssh, , .*, AzureADConnectAuthenticationAgentService.exe
TargetFilename7starts_with 3, wildcard 3, contains 1, ends_with 1, eq 1, in 1, match 1*/.claude/*, */.codex/*, */.config/github-copilot/*, /Library/Security/SecurityAgentPlugins/*, /boot/efi/EFI/*/grub.cfg
eventType7eq 5, contains 1, in 1application.lifecycle.update, user.authentication.auth_via_mfa, application.lifecycle.activate, application.lifecycle.create, system.idp.lifecycle
Image6is_not_null 2, starts_with 2, ends_with 1, wildcard 1, ./*, /boot/*, /bin/*, /dev/shm/*
OperationName6eq 5, contains 1, in 1Add member to group, Add named location, Add service principal, Authentication Methods Policy Update, Certificates and secrets management
Provider_Name6eq 6iam.amazonaws.com, rds.amazonaws.com, rolesanywhere.amazonaws.com, sts.amazonaws.com
aws::eventName6eq 5, in 1DeactivateMFADevice, DeleteVirtualMFADevice, CreateVirtualMFADevice, AssociateDirectory, DisableExternalIdPConfigurationForDirectory
operationName6eq 4, contains 2Disable Strong Authentication, Update conditional access policy, User registered security info, authentication methods policy update, set domain authentication

Top indicator values (753 distinct)

These values appear most often in rule predicates.

FieldKindValueRules (here)Corpus reach
event.outcomeeq
Success
10306
event.outcomeeq
success
382
sourcetypeeq
cisco:duo:administrator
1010
sourcetypeeq
cisco:duo:activity
44
actioneq
policy_create
88
actioneq
policy_update
88
data_stream.dataseteq
okta.system
735
data_stream.dataseteq
azure.auditlogs
423
data_stream.dataseteq
aws.cloudtrail
340
data_stream.dataseteq
aws.cloudtrail
3143
event.typeeq
start
61036
event.typeeq
creation
348
Actioneq
UPDATE
44
EventTypeeq
exec
4547
EventTypeeq
modification
272
Target.typeeq
TAILNET
44
action.nameeq
admin_login
33
log_sourceeq
auditevents
312
AttributeLDAPDisplayNameeq
msDS-KeyCredentialLink
22
EventTypein
ProcessRollup2
2119
EventTypein
exec
2180
EventTypein
exec_event
2135
Imageis_not_null
2155
Provider_Nameeq
iam.amazonaws.com
224
TargetObjectwildcard
HKLM\SYSTEM\*ControlSet*\Services\*\NetworkProvider\ProviderPath
22
aws::eventNameeq
CreateVirtualMFADevice
22
aws::eventNameeq
DeactivateMFADevice
22
aws::eventNameeq
DeleteVirtualMFADevice
22
azure_ad::authentication_requirementeq
singleFactorAuthentication
27
azure_ad::user_typeeq
Member
210

Exclusions (395 distinct)

These values appear most often in top-level exclusions.

FieldKindValueRules excluding
Detailseq
?:\Program Files (x86)\Citrix\ICA Client\x64\pnsson.dll
2
Imagein
./usr/bin/podman
2
Imagein
/bin/autossl_check
2
Imagein
/bin/chef-client
2
Imagein
/bin/dnf
2
Imagein
/bin/dnf-automatic
2
Imagein
/bin/dockerd
2
Imagein
/bin/dpkg
2
Imagein
/bin/dpkg-divert
2
Imagein
/bin/microdnf
2
Imagein
/bin/pacman
2
Imagein
/bin/pamac-daemon
2
Imagein
/bin/podman
2
Imagein
/bin/puppet
2
Imagein
/bin/rpm
2

Rules under this technique

These vendors publish rules tagged with this technique.

Platform (all)
Domain (all)

Sigma 20 rules

Elastic 46 rules

Splunk 35 rules

Kusto 32 rules

YARA-L 5 rules

Panther 31 rules