Techniques
Sample rules
Windows CertUtil Download With URL Argument
- source: splunk
- technicques:
- T1105
Description
The following analytic detects the use of certutil.exe to download files using the -URL arguments. This behavior is identified by monitoring command-line executions for these specific arguments via Endpoint Detection and Response (EDR) telemetry. This activity is significant because certutil.exe is a legitimate tool often abused by attackers to download and execute malicious payloads. If confirmed malicious, this could allow an attacker to download and execute arbitrary files, potentially leading to code execution, data exfiltration, or further compromise of the system.
Detection logic
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_certutil` (Processes.process="*-URL *" OR Processes.process="*/URL *") by Processes.dest Processes.user Processes.original_file_name Processes.parent_process Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_certutil_download_with_url_argument_filter`
CertUtil Download With URLCache and Split Arguments
- source: splunk
- technicques:
- T1105
Description
The following analytic detects the use of certutil.exe to download files using the -urlcache and -f arguments. It leverages Endpoint Detection and Response (EDR) data, focusing on command-line executions that include these specific arguments. This activity is significant because certutil.exe is typically used for certificate services, and its use to download files from remote locations is uncommon and potentially malicious. If confirmed, this behavior could indicate an attempt to download and execute malicious payloads, leading to potential system compromise and unauthorized data access.
Detection logic
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_certutil` Processes.process="*urlcache*" (Processes.process="*/f *" OR Processes.process="*-f *") by Processes.dest Processes.user Processes.parent_process Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.original_file_name Processes.parent_process_id
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `certutil_download_with_urlcache_and_split_arguments_filter`
CertUtil Download With VerifyCtl and Split Arguments
- source: splunk
- technicques:
- T1105
Description
The following analytic detects the use of certutil.exe to download files using the -VerifyCtl and -f arguments. This behavior is identified by monitoring command-line executions for these specific arguments via Endpoint Detection and Response (EDR) telemetry. This activity is significant because certutil.exe is a legitimate tool often abused by attackers to download and execute malicious payloads. If confirmed malicious, this could allow an attacker to download and execute arbitrary files, potentially leading to code execution, data exfiltration, or further compromise of the system.
Detection logic
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_certutil` Processes.process="*verifyctl*" (Processes.process="*/f *" OR Processes.process="*-f *") by Processes.dest Processes.user Processes.original_file_name Processes.parent_process Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `certutil_download_with_verifyctl_and_split_arguments_filter`