Conhost Spawned By Uncommon Parent Process

 1title: Conhost Spawned By Uncommon Parent Process
 2id: cbb9e3d1-2386-4e59-912e-62f1484f7a89
 3status: test
 4description: Detects when the Console Window Host (conhost.exe) process is spawned by an uncommon parent process, which could be indicative of potential code injection activity.
 5references:
 6    - https://www.elastic.co/guide/en/security/current/conhost-spawned-by-suspicious-parent-process.html
 7author: Tim Rauch, Elastic (idea)
 8date: 2022/09/28
 9modified: 2023/03/29
10tags:
11    - attack.execution
12    - attack.t1059
13logsource:
14    category: process_creation
15    product: windows
16detection:
17    selection:
18        Image|endswith: '\conhost.exe'
19        ParentImage|endswith:
20            - '\explorer.exe'
21            # - '\csrss.exe'  # Legitimate parent as seen in EchoTrail https://www.echotrail.io/insights/search/csrss.exe
22            # - '\ctfmon.exe'  # Seen several times in a testing environment
23            # - '\dllhost.exe'  # FP on clean system from grandparent 'svchost.exe -k DcomLaunch -p'
24            - '\lsass.exe'
25            - '\regsvr32.exe'
26            - '\rundll32.exe'
27            - '\services.exe'
28            - '\smss.exe'
29            - '\spoolsv.exe'
30            - '\svchost.exe'
31            - '\userinit.exe'
32            # - '\wermgr.exe'  # Legitimate parent as seen in EchoTrail https://www.echotrail.io/insights/search/wermgr.exe
33            - '\wininit.exe'
34            - '\winlogon.exe'
35    filter_main_svchost:
36        ParentCommandLine|contains:
37            - '-k apphost -s AppHostSvc'
38            - '-k imgsvc'
39            - '-k localService -p -s RemoteRegistry'
40            - '-k LocalSystemNetworkRestricted -p -s NgcSvc'
41            - '-k NetSvcs -p -s NcaSvc'
42            - '-k netsvcs -p -s NetSetupSvc'
43            - '-k netsvcs -p -s wlidsvc'
44            - '-k NetworkService -p -s DoSvc'
45            - '-k wsappx -p -s AppXSvc'
46            - '-k wsappx -p -s ClipSVC'
47    filter_optional_dropbox:
48        ParentCommandLine|contains:
49            - 'C:\Program Files (x86)\Dropbox\Client\'
50            - 'C:\Program Files\Dropbox\Client\'
51    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
52falsepositives:
53    - Unknown
54level: medium