Detection rules › Elastic
Unusual Kerberos Client Process
Identifies network connections to the standard Kerberos port from an unusual process. On Windows, the only native system process that normally performs Kerberos traffic from a domain joined host is lsass.exe.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Credential Access |
Rule body
[rule]
description = """
Identifies network connections to the standard Kerberos port from an unusual process. On Windows, the only native system
process that normally performs Kerberos traffic from a domain joined host is lsass.exe.
"""
id = "b5c91c3e-9d2d-4df6-afb7-c9d236b5ebe2"
license = "Elastic License v2"
name = "Unusual Kerberos Client Process"
os_list = ["windows"]
version = "1.0.32"
query = '''
sequence by process.entity_id with maxspan=1m
[any where user.id like ("S-1-5-21*", "S-1-12-*") and
(
(event.category =="library" and dll.name : ("System.DirectoryServices.*.dll", "Wldap32.dll")) or
(event.category in ("network", "dns") and dns.question.name : "_ldap._tcp.*")
)]
[network where destination.port == 88 and source.port >= 49152 and
network.direction == "egress" and network.transport == "tcp" and
not destination.address : ("127.*", "::1", "66.64.*") and
not process.executable :
("?:\\Program Files (x86)\\GFI\\LanGuard 12 Agent\\lnsscomm.exe",
"?:\\Program Files\\Microsoft Azure Active Directory Connect\\AzureADConnect.exe",
"?:\\Program Files (x86)\\GalacticAgent\\bin\\GalacticScan.exe",
"?:\\Xelis Dental Trainer\\Bin-x64\\XelisDental.exe")]
'''
min_endpoint_version = "7.16.0"
[[actions]]
action = "kill_process"
field = "process.entity_id"
state = 0
[[optional_actions]]
action = "rollback"
field = "process.entity_id"
state = 0
[[threat]]
framework = "MITRE ATT&CK"
[[threat.technique]]
id = "T1558"
name = "Steal or Forge Kerberos Tickets"
reference = "https://attack.mitre.org/techniques/T1558/"
[threat.tactic]
id = "TA0006"
name = "Credential Access"
reference = "https://attack.mitre.org/tactics/TA0006/"
[internal]
min_endpoint_version = "7.16.0"
Stages and Predicates
Ordered sequence: each step below must occur in order within 1m, correlated by process.entity_id.
Stage 1: any
[any where user.id like ("S-1-5-21*", "S-1-12-*") and
(
(event.category =="library" and dll.name : ("System.DirectoryServices.*.dll", "Wldap32.dll")) or
(event.category in ("network", "dns") and dns.question.name : "_ldap._tcp.*")
)]
Stage 2: network
[network where destination.port == 88 and source.port >= 49152 and
network.direction == "egress" and network.transport == "tcp" and
not destination.address : ("127.*", "::1", "66.64.*") and
not process.executable :
("?:\\Program Files (x86)\\GFI\\LanGuard 12 Agent\\lnsscomm.exe",
"?:\\Program Files\\Microsoft Azure Active Directory Connect\\AzureADConnect.exe",
"?:\\Program Files (x86)\\GalacticAgent\\bin\\GalacticScan.exe",
"?:\\Xelis Dental Trainer\\Bin-x64\\XelisDental.exe")]
Exclusions
The rule actively suppresses these predicates.
| Field | Kind | Excluded values | Search |
|---|---|---|---|
destination.address | wildcard | 127.*, ::1, 66.64.* | excludes:destination.address field:"destination.address" value:"127.*" field:"destination.address" value:"::1" field:"destination.address" value:"66.64.*" |
process.executable | eq | ?:\Program Files (x86)\GFI\LanGuard 12 Agent\lnsscomm.exe, ?:\Program Files\Microsoft Azure Active Directory Connect\AzureADConnect.exe, ?:\Program Files (x86)\GalacticAgent\bin\GalacticScan.exe, ?:\Xelis Dental Trainer\Bin-x64\XelisDental.exe | excludes:process.executable |
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
destination.port | eq |
| field:"DestinationPort" kind:eq value:"88" |
dll.name | wildcard |
| field:"dll.name" kind:wildcard |
dns.question.name | wildcard |
| field:"QueryName" kind:wildcard value:"_ldap._tcp.*" |
event.category | eq |
| field:"event.category" kind:eq value:"library" |
event.category | in |
| field:"event.category" kind:in |
network.direction | eq |
| field:"Initiated" kind:eq value:"egress" |
network.transport | eq |
| field:"Protocol" kind:eq value:"tcp" |
source.port | ge |
| field:"SourcePort" kind:ge value:"49152" |
user.id | wildcard |
| field:"user.id" kind:wildcard |