Detection rules › Splunk
DLLHost with no Command Line Arguments with Network
The following analytic detects instances of DLLHost.exe running without command line arguments while establishing a network connection. This behavior is identified using Endpoint Detection and Response (EDR) telemetry, focusing on process execution and network activity data. It is significant because DLLHost.exe typically runs with specific arguments, and its absence can indicate malicious activity, such as Cobalt Strike usage. If confirmed malicious, this activity could allow attackers to execute code, move laterally, or exfiltrate data, posing a severe threat to the network's security.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Privilege Escalation | T1055 Process Injection |
| Defense Evasion | T1055 Process Injection |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Sysmon | 1 | Process creation |
| Sysmon | 3 | Network connection |
Stages and Predicates
Stage 1: tstats
tstats WHERE (Processes.original_file_name="dllhost.exe" OR Processes.process_name="dllhost.exe") Processes.process IN ("*dllhost", "*dllhost.exe", "*dllhost.exe\"") BY _time, host, Processes.action, Processes.dest, Processes.original_file_name, Processes.parent_process, Processes.parent_process_exec, Processes.parent_process_guid, Processes.parent_process_id, Processes.parent_process_name, Processes.parent_process_path, Processes.process, Processes.process_exec, Processes.process_guid, Processes.process_hash, Processes.process_id, Processes.process_integrity_level, Processes.process_name, Processes.process_path, Processes.user, Processes.user_id, Processes.vendor_product
Stage 2: search
search
Stage 3: search
search
Stage 4: search
search
Stage 5: rename
rename
Stage 6: join
join type=inner (...)
Stage 7: search
search `macro`
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
All_Traffic.dest_port | ne |
|
Processes.original_file_name | eq |
|
Processes.process | in |
|
Processes.process_name | eq |
|